After six years of Republican rule, the Senate could very well flip.
By now, the reasons are clear.
A majority of the country never approved of President Donald Trump, or his handling of his top crisis, the coronavirus pandemic, which shuttered businesses and claimed the lives of over 230,000 people in America.
Democratic candidates bet that protecting and expanding upon the Affordable Care Act, which ended their party's control of the Senate in 2014, would be their path back to power.
And Republican senators warned that their loss would lead to socialism, even though Americans increasingly desire for the government to do more to address the country's problems, according to Pew Research, and former Vice President Joe Biden, the epitome of the establishment, took over the Democratic Party.
Republicans control 53 Senate seats. Democrats need to win a net gain of three, and the White House, to take back the chamber.
At least a dozen Republican Senate seats are now at risk, including two in blue states -- Maine and Colorado -- and 10 in states Trump won in 2016 -- Arizona, Georgia, Iowa, Montana, North Carolina, South Carolina, Alaska, Kansas and Texas (Georgia has two Senate races). Democrats are defending only two seats -- in Alabama and Michigan -- in competitive contests.
Republicans hope that an economic rebound and the late confirmation of Supreme Court Justice Amy Coney Barrett will remind voters why they put the GOP in charge, and save their Senate majority.
But there are a number of other factors that could determine the future control of the Senate. Here are nine to watch:
1. Will the Senate and presidential results match perfectly like they did in 2016?
The 2016 election cycle was the first in which every state voted for the same party in both the presidential and Senate races.
If that's the case again in 2020, then the Republicans should benefit, since many of the competitive Senate contests are in red states.
Maine Republican Sen. Susan Collins and Colorado Republican Sen. Cory Gardner would lose their seats, but Republican candidate Tommy Tuberville would defeat Alabama Democratic Sen. Doug Jones. The outcome of the Senate would then be determined by how well Trump does in close battleground states like North Carolina, Iowa, Arizona, Georgia and even Texas.
The margin of the presidential race cuts both ways. It will be crucial in states like Michigan and Minnesota, where Trump is expected to lose, and also in others like Montana and South Carolina, where the President should easily win.
John James, a Republican businessman who flew Army helicopters in the Iraq War, is trying to oust Michigan Democratic Sen. Gary Peters and become the state's first Black senator. While James has criticized the President for cutting Great Lakes funding and calling some African countries "shitholes," Democrats have tried to tie Trump around him, noting that he said he supported Trump's agenda "2,000%" in 2018. Still, James and other Republican candidates in close races, including Georgia Sen. David Perdue and North Carolina Sen. Thom Tillis, have campaigned with Trump in the last couple months of the race, understanding that the base of the party loves him.
Collins, the last GOP member of Congress in New England, has put more distance between herself and the President, declining to say whether she will vote for him. Collins, the only Republican to oppose Barrett's confirmation, did not attend a recent rally in her state with Vice President Mike Pence. Some polls show that her state is rewarding Collins' unique brand, with Trump easily losing Maine but the senator neck and neck with Democratic candidate Sara Gideon.
Some Democrats in Trump-won states have avoided confronting the President, including Montana Gov. Steve Bullock, who ran for the Democratic nomination to take on Trump, but is now running against Republican Sen. Steve Daines on a health care-focused platform. But Republicans have attempted to tie Bullock to Biden, Senate Democratic Leader Chuck Schumer and House Speaker Nancy Pelosi. At a Halloween rally in Montana, Donald Trump Jr. said that Bullock and other Montana Democratic candidates are "dressed up as though they're not radical liberals every day of the year."
The country has become increasingly partisan, and split-ticket voting is rare. Only 4% of registered voters say they will support Trump or Biden and a Senate candidate from the opposing party, according to the Pew Research Center. Since 2012, 88% of the 139 Senate candidates were of the same party that won the state's most recent presidential election.
2. Will there be a red or blue mirage on Election Day?
The pandemic has fundamentally changed how people vote and count ballots. In Texas, where Sen. John Cornyn faces Democratic candidate MJ Hegar, over 9.7 million people have already voted, more than the Lone Star state's total in 2016, according to data company Catalist, a company that provides data, analytics and other services to Democrats, academics and nonprofit issue-advocacy organizations. In North Carolina, where Republican Sen. Thom Tillis faces a tough race against Democrat Cal Cunningham, over 4.5 million people have already voted, only about 200,000 fewer than the Tar Heel state's total in 2016.
Both states could see a so-called "blue mirage" because the states started processing mail ballots before Election Day, and the first results to become public will include early votes, which favor Democrats.
The opposite, a "red mirage," could occur in Michigan, where Democratic Sen. Gary Peters faces Republican candidate John James, and in Minnesota, where Democratic Sen. Tina Smith faces former Republican Rep. Jason Lewis, as absentee ballots get counted late on Tuesday night.
3. Will Georgia's Senate races go to a runoff?
Perdue and the other Republican senator from Georgia, Kelly Loeffler, are both facing elections in 2020.
Perdue, who first won his seat in 2014, is facing reelection against Democrat Jon Ossoff and libertarian candidate Shane Hazel. If no candidate gets more than 50% on Election Day, the two top vote-getters will compete in a runoff on January 5.
While that could happen in Perdue's race, a runoff is "almost absolutely certain" to happen in Loeffler's, according to Dr. Charles Bullock, a political science professor at the University of Georgia.
Late last year, Georgia Gov. Brian Kemp appointed Loeffler to replace Sen. Johnny Isakson, who resigned over health concerns. The winner of the special election will serve until 2022, when Isakson's term ends. The melee format is unusual, with all candidates regardless of party thrown together in the race. Loeffler is facing 20 candidates, including GOP Rep. Doug Collins and Democrat Raphael Warnock, the senior pastor of the Ebenezer Baptist Church in Atlanta.
Bullock said that Republicans in Georgia have been better than Democrats in turning out their voters during runoff elections, noting that in 2008, the drop off in voters was more dramatic among black voters than white voters, helping then-Republican Sen. Saxby Chambliss defeat Democrat Jim Martin.
"What might change it would be to have Reverend Warnock, an African American, in the runoff," said Bullock.
Loeffler and Collins have viciously attacked each other for months, directly delivering their messages to the most conservative voters, leaving Warnock an opportunity to attract both Democrats and independents. Still, neither GOP candidate has expressed any hesitation on their race to the right.
"I don't have to move anywhere in this race," Collins recently told CNN. "Georgia is a conservative state and always has been."
4. Will ranked-choice voting hurt Maine Sen. Susan Collins?
Maine Sen. Susan Collins' reelection race against Democrat Sara Gideon could decide which party wins the Senate. But Republicans worry that the state's ranked-choice voting system could hurt Collins since two third-party candidates, Max Linn and Lisa Savage, are also on the ballot.
In Maine, a candidate needs to not only get more votes than the other candidate, but at least 50% of the votes. If no candidate gets a majority, then Maine's Senate election gets trickier.
The Pine Tree state allows voters to rank candidates in order of preference on the ballot. Voters can select a first choice, second choice, third choice, fourth choice, et cetera.
If no Senate candidate receives a majority of the vote this year, then the fourth-ranked candidate will be eliminated, and their votes will be reallocated to the other candidates based on who they ranked second. If no candidate hits 50%, the third-place candidate will then have their votes reapplied to the top two candidates, again based on if and how they ranked other preferences.
If the race turns to a second round of voting, Collins could suffer. A September New York Times/Siena College poll showed that Gideon held a lead over Collins, but did not reach 50%. Savage, a Maine Green Independent Party candidate running to the left of Gideon on a pro-Medicare for All and pro-Green New Deal platform, is urging her supporters to rank the Democrat second. That could prove pivotal if no candidate initially hits a majority.
When ranked-choice voting tabulation rounds are initiated, couriers are sent around the state to either collect actual ballots or memory devices and bring them to a secure location in Augusta, the state's capital. There, high speed tabulators process the ballots, and memory devices are uploaded. A secure computer is then used to determine the results by applying the ranked-choice voting rules.
That process can take between one and two weeks to complete, so if no candidate wins outright on November 3, the winner will not be clear on election night.
In 2018, Democrat Jared Golden defeated Republican Rep. Bruce Poliquin in a Maine House race even though Poliquin led in the first round of votes. Golden was announced the winner nine days after Election Day.
"It is unlikely that any candidate will get a majority of the vote in the first round of balloting," said Mark Brewer, a political science professor at the University of Maine. "If ranked choice is necessary, it will absolutely cause a delay in determining the winner of the race."
5. Will a sex scandal sink a Democrat in North Carolina?
About a month before Election Day, text messages and reports detailing Senate Democratic candidate Cal Cunningham's alleged extramarital affair this summer undercut the image he carefully crafted as a man of integrity who serves in the Army Reserve. But while voters disapproved, he still has the edge over incumbent Republican Sen. Thom Tillis, according to polls.
Before the sex scandal emerged, Cunningham was up 42% to 37%, according to a Times/Siena poll from mid-September. Since then, CNN released a poll showing that Cunningham's lead narrowed to 47% to 44%, due in large part because his deficit with men was slightly smaller than his advantage with women.
Denise Adams, a Winston-Salem city council member, told CNN that women "realize what's at stake," adding that health care, abortion access and education funding are all on the ballot.
"I ain't trying to call nobody's pot kettle black," she added. "Right now, Democrats in North Carolina are united, and our task ahead of us is to bring this baby home."
But Republicans are hopeful that the scandal could cost Democrats the seat and their hopes of winning the Senate majority.
Andrew Romeo, a Tillis spokesman, told CNN that while Cunningham is "in hiding" and under investigation by the Army Reserve for his conduct, the senator is "sprinting to the finish line" with a statewide public tour.
"We are confident that this contrast will make the difference in this tight race and lead to Senator Tillis' victory on Tuesday," said Romeo.
Rachel Petri, a Cunningham spokesperson, responded that the Democratic candidate is "connecting directly with voters to talk about the issues that actually matter in their lives like accessing health care, raising wags, and responding to this virus."
"Senator Tillis can't defend his record on the issues, which is why he's forced to spend the final hours of this campaign making desperate, personal attacks in a last ditch effort to save his political career," she added.
6. Will a third-party candidate doom Sen. Lindsey Graham?
Bill Bledsoe, the third-party candidate in the surprisingly close Senate contest between South Carolina Republican Sen. Lindsey Graham and Democrat Jaime Harrison, does not want anyone to vote for him. A month ago, he dropped out and endorsed Graham.
But the conservative, Constitution Party candidate will still be on the ballot, potentially damaging Graham's bid for a fourth term.
The Harrison campaign, which raised $57 million between July and September, the largest single-quarter total by any candidate in US Senate history, has plenty of resources. So the group has aired television ads in an attempt to boost Bledsoe with Republican voters, saying he is too conservative, pro-Trump, anti-abortion and pro-gun for South Carolina. Some of the ads show images of the ballot with Bledsoe's name highlighted.
Harrison's campaign, along with two outside groups -- Duty and Country, a Democratic Super PAC aligned with Senate Democratic Leader Chuck Schumer, and the Lincoln Project, a group of former Republicans -- have spent millions on the ads, according to Kantar's Campaign Media Analysis Group.
Trump won South Carolina by 14 points in 2016 but leads Biden by eight points, according to a New York Times/Siena College poll in October. Graham led Harrison 46% to 40%.
But other polls have shown a closer contest, and Democrats are hopeful that Bledsoe's candidacy could help Harrison win. The last Democratic candidate to win a statewide race in South Carolina, South Carolina Superintendent of Education Jim Rex, defeated a Republican in 2006 by 455 votes when four third-party candidates also ran for the office.
"That's going to be huge for Jaime," Amanda Loveday, a former executive director of the South Carolina Democratic Party, told CNN last month. "[Bledsoe's] name will appear on every ballot in the state of South Carolina. And if you vote for him, it could potentially determine the results of the election."
7. What can money buy?
Political groups have spent over $1.7 billion to advertise in Senate races, according to CMAG. Democrats spent 54% of that figure, after their candidates won the fundraising battle and broke state records.
The disparity between the Republican senators and their Democratic challengers was particularly acute between July and September. In the battleground states of Maine, North Carolina, Iowa, Arizona, Georgia, Montana and Colorado, the Democratic candidates outraised the Republican senator in each state between about $15 million and $31 million.
But even in red states, the Democrats outraised the incumbent by astonishing figures. In South Carolina, Harrison raised $29.4 million more than Graham. In Kentucky, Democrat Amy McGrath raised $21 million more than Senate Majority Leader Mitch McConnell. In Kansas, former state legislator Barbara Bollier raised $10 million more than GOP Rep. Roger Marshall. In Alaska, Al Gross, a political independent running as the Democratic nominee, raised $7.3 million more than Republican Sen. Dan Sullivan. And in Texas, MJ Hegar raised $6.7 million more than Sen. John Cornyn.
ActBlue, the Democrats' online fundraising portal, said it broke its single-day record three times in September, raising $43.2 million on September 29, the day of the first presidential debate, $66.9 million on September 30, the last day of the financial quarter, and $70.6 million on September 19, the day after Justice Ruth Bader Ginsburg died.
Some Republican strategists said that Democrats were throwing good money at bad races.
"Yes, they're being outspent heavily with all this national money," said GOP strategist Scott Reed. "But at the end of the day, I'm convinced they're going to hold the Senate."
Reed told CNN that it was "shocking" Harrison raised all that money, but was "convinced" Graham, the Senate Judiciary Committee chairman, would win. He said Trump would win the state by double digits and voters would reward Graham for leading the Senate confirmation of Ginsburg's replacement, the conservative Justice Amy Coney Barrett. "That's a big deal," he said.
Reed called Steven Law, a former chief of staff to McConnell, and his constellation of outside groups as the "MVP" of the 2020 election cycle. In the face of extremely well funded Democratic candidates, the conservative groups have had to save more than one Republican Senate campaign.
Overall, the groups -- the Senate Leadership Fund, One Nation, Plains PAC, Defend Arizona, Keep Kentucky Great and the Faith and Power PAC -- combined spent over $310 million on ads, more than any other organization except the Trump and Biden campaigns, according to CMAG.
The National Republican Senatorial Committee spent over $79 million. And other groups typically aligned with the right spent even less; The Chamber of Commerce spent about $6 million.
Outside groups also boosted the Democrats. The Senate Majority PAC, a Super PAC aligned with Schumer and led by strategist JB Poersch, along with Duty and Honor, Majority Forward and the Sunflower State PAC, spent over $246 million on ads, according to CMAG. The Democratic Senatorial Campaign Committee spent over $73 million.
8. Record number of Black candidates run for Senate in the South
The Deep South is fielding more Black Senate candidates than it has since Reconstruction. Marquita Bradshaw, a community organizer and the first Black woman to win a statewide nomination in Tennessee, is running against Republican candidate Bill Hagerty, Trump's former ambassador to Japan. Adrian Perkins, the mayor of Shreveport, faces Republican Sen. Bill Cassidy. And Mike Espy, who was Secretary of Agriculture under President Bill Clinton, is trying to defeat Sen. Cindy Hyde-Smith and far outraising her.
None of these three candidates are expected to win their deeply conservative states. But Harrison in South Carolina and Warnock in Georgia have put their race in play.
These Black candidates ran as the country grappled with a reckoning over race, following the police killing of George Floyd. Republicans attacked Democratic candidates for the liberal proposal to defund the police, which would reallocate funds from law enforcement to other local government agencies. Loeffler said at a recent rally in Buford, Georgia, that the idea is "absolutely insane."
"We have to keep our communities safe," she said. The senator later said that Warnock has refused to apologize for saying some police officers act like gangsters and thugs, which he said in a sermon after Michael Brown's 2015 killing in Ferguson, Missouri.
When Loeffler asked the pastor about those comments at a recent debate, Warnock said he had "deep respect" for law enforcement but wanted the country to have "equal protection under the law."
Loeffler, the co-owner of the Atlanta Dream, sparked a backlash over the summer when she wrote to WNBA commissioner that she "adamantly" opposed the Black Lives Matter movement. Some players wore t-shirts that said, "Vote Warnock."
In a recent interview, Warnock focused his comments on health care, talking about expanding Medicaid and protecting the insurance of those with pre-existing conditions. But when asked about Loeffler's dispute with her own team, Warnock said it was a "sad and cynical move by a desperate politician, trying to shore up her base at any cost."
"Kelly Loeffler may have the privilege of playing politics with this issue, but I come from a community where the issue of police brutality is real and it's a matter of life and death," he added. When asked if he aligned himself with BLM, Warnock responded, "Black Lives Matter."
9. Will Women Flip the Senate?
If Democrats do take back the Senate, it will be because of women.
There has long been a gender gap in American politics, with women favoring the Democratic Party and men favoring the Republican Party. The biggest gaps were in 2016 and 1996, when 41% of women and 52% of men supported Trump, and 55% of women and 44% of men supported Democratic President Bill Clinton, according to Rutgers' Center for American Women and Politics. Some polls suggest that Trump's presidency could widen that gap in 2020.
In Senate polls across the country, many Democratic candidates have a double-digit difference in their support between women and men.
"I know it's gonna be close, but I actually do feel like we are in position to take back the Senate," Stephanie Schriock, president of EMILY's List, told CNN.
Schriock said she was "really, really pleased" that Democratic candidates like Theresa Greenfield in Iowa, Barbara Bollier in Kansas and MJ Hegar in Texas put their races on the map. These Trump-won states have been surprisingly competitive; Kansas hasn't elected a Democrat to the Senate since 1932.
A significant gender gap is present in a number of Senate races, according to a series of New York Times/Siena College polls the past two months.
In Arizona, Democratic candidate Mark Kelly, a NASA astronaut and the husband of former Arizona Rep. Gabby Giffords, led in his bid to oust Sen. Martha McSally because his deficit with men was smaller than his substantial advantage with women. He garnered 57% of support from women but only 44% of men.
In Iowa, Greenfield narrowly trailed Sen. Joni Ernst. While she received 50% of support from women, only 37% of men backed her.
And in Maine, Gideon, the state House speaker, led Collins because she tied her with men and captured the support of a plurality of the women.
Schriock said that Republican efforts to attack the Affordable Care Act, block legislation addressing the gender pay gap and their anti-abortion views have made the GOP unpopular with women.
"And then there's his behavior, and the chaos that he produces constantly," said Schriock, referring to the President. "[It] is just not anything women voters are interested in right now."
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