The battle for the Senate is running down to the wire.

While Democrats hold a narrow edge heading into the final week of the election campaign, races in battleground states remain too close to call.

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Democrats need to pick up five seats — or four if they retain the White House — to win back control of the upper chamber.

The nonpartisan Cook Political Report predicts that they’ll pick up as many as seven seats — though that was before the FBI announced Friday that it was looking into newly recovered emails from former New York Rep. Anthony Weiner’s account that were related to an earlier investigation of Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE.

The late curveball made huge headlines, and could change momentum in down-ballot races.

Democrats for months have seen GOP-held seats in Wisconsin and Illinois as likely pickups, but the race for Sen. Ron Johnson Ronald (Ron) Harold Johnson CIA found Putin 'probably directing' campaign against Biden: report This week: Supreme Court fight over Ginsburg's seat upends Congress's agenda GOP set to release controversial Biden report MORE’s (R-Wis.) seat may be tightening. A Democratic super PAC has gone on the air with new advertisements in the state, which could suggest some concern about the outcome.

In Illinois, the latest news helped Democrats. At a Thursday debate, Sen. Mark Kirk Mark Steven KirkLiberal veterans group urges Biden to name Duckworth VP On the Trail: Senate GOP hopefuls tie themselves to Trump Biden campaign releases video to explain 'what really happened in Ukraine' MORE (R-Ill.) made a cutting comment about Democratic Rep. Tammy Duckworth’s Asian heritage. Kirk apologized for the comments a day later.

Here’s a breakdown of the seven other fights that could determine who controls the Senate:

Florida: Rubio vs. Murphy

Sen. Marco Rubio Marco Antonio RubioOvernight Defense: Pentagon redirects pandemic funding to defense contractors | US planning for full Afghanistan withdrawal by May | Anti-Trump GOP group puts ads in military papers Democrats step up hardball tactics as Supreme Court fight heats up Press: Notorious RBG vs Notorious GOP MORE (R) has long been considered the front-runner for his critical seat, leading nearly every poll against Democratic Rep. Patrick Murphy since jumping back into the race in late June.

This prompted national Democrats to essentially write off the race and move resources to new pickup opportunities in Missouri and North Carolina, which also have cheaper media markets.

The shifting of dollars angered top Democrats who believe the race is a chance to extinguish Rubio’s future White House ambitions. They point to recent polls that have Murphy closing the gap, arguing there’s a glimmer of hope in the Sunshine State.

In light of the polls, the main Democratic Senate super PAC is funneling seven figures into a Florida super PAC to boost Murphy.

Still, Rubio will be the favorite.

He leads by more than 3 points in the RealClearPolitics polling average. And at the top of the ticket, Republican nominee Donald Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE is cutting into Clinton’s already slim lead.

Indiana: Bayh vs. Young

Former Sen. Evan Bayh’s entry into the race was the counterpunch to Rubio’s candidacy. The Democrat, a household name in Indiana, was initially viewed as the overwhelming favorite.

He maintains his edge, but the race has tightened in recent weeks as critics continue to challenge his residency in Indiana, as well as his lobbying ties following his 2010 Senate retirement.

Bayh’s double-digit lead was cut in half, and RealClearPolitics has him leading Rep. Todd Young Todd Christopher YoungSenate GOP eyes early exit Why the US should rely more on strategy, not sanctions Davis: The Hall of Shame for GOP senators who remain silent on Donald Trump MORE (R) by less than 4 points.

Indiana is still a main target for Democrats, but the nature of the traditionally red state complicates Bayh’s path. Trump’s comfortable lead in the Hoosier State means Democrats will need to rely on Republican voters who are willing to split their tickets in down-ballot races.

Missouri: Blunt vs. Kander

Democrats believe Jason Kander is their best recruit of the cycle. The 35-year-old secretary of State has turned what was considered a long-shot race into a dead heat.

Kander has spent months using an anti-Washington message to hammer Sen. Roy Blunt Roy Dean BluntSocial media platforms put muscle into National Voter Registration Day Senate GOP faces pivotal moment on pick for Supreme Court This week: Supreme Court fight over Ginsburg's seat upends Congress's agenda MORE (R) — a member of GOP leadership — who has spent years in Congress and whose family has deep lobbying ties.

He’s not the first Democrat to try the tactic, but his message is finding roots in a year driven by voter frustration and a presidential election shaped by outsiders.

Blunt and Republicans have tried to reverse the script by linking Kander to Clinton and to Washington, D.C., donors. They argue Blunt is bolstered by the fact that Missouri is expected to swing decisively for Trump at the top of the ticket.

Polls show the race is basically tied, with Blunt leading on average by a percentage point, according to RealClearPolitics.

Nevada: Heck vs. Cortez Masto

Trump is looming large over Nevada in the final stretch of the election campaign.

Republican Rep. Joe Heck’s decision to drop support for his party’s presidential nominee earned him conservative backlash.

But with polls in his own race tightening, he’s waffled.

Heck said during a fundraiser he would like to be able to support Trump, before telling a local reporter that he won’t say how he’ll vote before the election.

Nevada is the best pickup opportunity for Republicans, who publicly relish being able to flip the seat held by Senate Democratic Leader Harry Reid Harry Mason ReidThe Supreme Court vacancy — yet another congressional food fight Trump seeks to turn around campaign with Supreme Court fight On The Trail: Battle over Ginsburg replacement threatens to break Senate MORE, a top GOP antagonist.

Heck is leading by an average 1.4 points over former Nevada Attorney General Catherine Cortez Masto, according to RealClearPolitics.

But Democrats have pledged for months that the race was closer than polls showed and are banking on mobilizing the state’s sizable Hispanic population. Reid — in his final political fight as he heads toward retirement — is also putting his machine to work for Masto.

New Hampshire: Ayotte vs. Hassan

The Granite State race is evidence that Republicans can hang on, despite Sen. Kelly Ayotte Kelly Ann AyotteBottom line Bottom line Bottom Line MORE’s (R) wavering support of Trump and Clinton’s solid, consistent lead in the state.

Ayotte stumbled at one of the debates by calling Trump a “role model” before quickly walking it back to say she “misspoke.” After the revelation of the 2005 tape showing Trump bragging about groping and kissing women without consent, she cut ties with her party’s nominee.

But her disavowal of Trump hasn’t appeared to rattle her base, which she will need in the pure toss-up seat, as Ayotte clings to a razor-thin lead.

Ayotte and the Democratic candidate, Gov. Maggie Hassan, have both proved to be strong campaigners with long histories in elected office, so the Senate race will likely hinge on what happens in the presidential race. If Clinton wins by a large enough margin, it’ll make it difficult for Ayotte to outperform her party’s nominee.

North Carolina: Burr vs. Ross

Republicans are growing worried about Sen. Richard Burr Richard Mauze BurrRep. Mark Walker says he's been contacted about Liberty University vacancy Overnight Defense: Trump rejects major cut to military health care | Senate report says Trump campaign's Russia contacts posed 'grave' threat Senate report describes closer ties between 2016 Trump campaign, Russia MORE, whose congressional tenure spans 22 years. He looks to be increasingly vulnerable in an unexpected marquee Senate race.

Democrats have redirected funds from other down-ballot races to help boost former state Sen. Deborah Ross, who has proved to be a solid campaigner and fundraiser.

The race has grown increasingly negative and personal, underscoring the importance of the seat. Democrats are painting Burr as a creature of Washington who has skipped a majority of Armed Services Committee hearings, while Republicans criticize Ross’s time as state director of the American Civil Liberties Union and her past concerns over a state sex offender registry.

Burr has regained a bit of an edge and is ahead by about 3 points. But a new poll released Friday shows the race in a dead heat. His steadfast support for Trump could be hurting him in a state where Clinton holds a slim but steady lead.

Pennsylvania: Toomey vs. McGinty

GOP Sen. Pat Toomey’s biggest hurdle is not his Democratic challenger but the nominee of his own party.

The straight-laced incumbent is being dogged by questions about whether he will support Trump — despite disagreeing with him — as the campaign heads into the home stretch.

But experts say the political limbo, while awkward, is his best option: breaking with Trump could cost him the conservative base, but embracing the volatile standard-bearer could risk moderate voters in a state that swings blue in presidential years.

Toomey maintains a narrow lead over Democrat Katie McGinty and has pitched himself as a check on a Clinton White House. He’s also tried to make an issue out of McGinty’s ethics as Clinton’s email server continues to haunt Democrats.

The fate of the race is inextricably linked to the White House fight. Trump needs to stick within 5 to 6 points of Clinton in Pennsylvania to give Toomey a fighting chance.