Democrats head into this Election Day hoping to widen the majorities they hold in both chambers of Congress when voters go to the polls, even holding out a glimmer of hope for a filibuster-proof 60-seat majority in the Senate.
And if they do, it would mean ousting some GOP stalwarts.
Several big names and longtime incumbents face tough ballot battles today, with Republican Minority Leader Sen. Mitch McConnell, R-Ky., and Sen. Elizabeth Dole, R-N.C., embroiled in stern challenges to hold onto their seats.
With a current 51-49 Senate majority, if Democrats hold all of their own seats and pick up nine more today -- a tall order indeed -- they would reach a filibuster-proof 60, at least on the occasions that the party votes in unison.
The so-called super-majority would allow Democrats to prevent Republicans from slowing or stopping legislation. The last time there was a filibuster-proof Senate was more than 30 years ago in 1977, during President Jimmy Carter's administration.
Even if they don't hit 60, today's voting could earn the Democrats enough seats to at least get close, thanks to the surging popularity at the top of their ticket and the suffering reputation of the GOP. Several experts predict the party has a strong likelihood of picking up seven or eight seats among the 11 most hotly-contested Senate races, putting them on the cusp of achieving a powerful voting majority.
ABCNews.com has focused on six key Senate races where, if the Democrats succeed, the party will take a strong hold of the Senate.
The Republican pedigree doesn't get any longer than Dole's, but she's facing a stiff battle from Democratic challenger Kay Hagan, who is benefiting from Sen. Barack Obama's popularity and support in the state.
Having served in both the Ronald Reagan and George H.W. Bush presidential administrations before becoming the first female senator from North Carolina, Dole's legacy seemed almost impossible to overcome.
But early voting numbers in North Carolina have shown a large turnout of African American voters, an indication that Obama's relentless campaigning in the state might be paying off for Hagan.
"This is an example of a Democratic senator riding on Obama's coattails," said Jennifer Duffy, the senior editor at The Cook Political Report. "At least 500,000 early voters have been African American, and Elizabeth Dole isn't getting those votes."
A Dole defeat would make it the first time in 35 years that the state has not voted a Republican into the Senate.
Princeton presidential historian Julian Zelizer says that in addition to benefiting from a large youth and African American turnout at the polls, Hagan is also profiting from Dole's association with the GOP.
"North Carolina is a case where you can see the Republicans being turned into the establishment party," said Zelizer. "Republicans were once the mavericks in Washington and the voices of change, but now after eight years of the Bush administration Dole has been effectively painted as a Washington insider."
"North Carolina is a bellweather in terms of the Republican party and how much that anti-establishment tactic [used by Democrats] is going to diminish Republican numbers," said Zelizer.
Most recently, a negative campaign ad released by Dole just days before the election referred to Hagan as "godless."
In the ad, Dole suggests that Hagan has received money from the "Godless Americans" PAC, and an actress with a voice similar to Hagan's is heard saying, "There is no God."
In an ad of her own later that same day, Hagan defended herself against the ad, which she called "offensive."
"I believe in God," Hagan says in the ad. "I taught Sunday School."
"My faith guides my life and Sen. Dole knows it," says Hagan, who has since filed a defamation lawsuit against Dole over the ad.
The ads have taken over the media's attention and much of the public has reacted negatively.
But some say the ads -- as negative as they are -- could benefit Dole and actually garner her votes from conservative voters.
The latest poll administered by CNN/Time/ORC on Oct. 28 shows Hagan leading Dole by nine percentage points, 53-44.
Not even the Republican leadership is safe: McConnell is in for a tough race against Democrat Bruce Lunsford.
Lunsford has spent the campaign capitalizing on McConnell's obvious association with the GOP, making Kentucky's Senate race yet another that may be affected by the waning support of the Republican Party.
Symbolically, political experts say a Democratic win in Kentucky would be "a great defeat" for Republicans, and losing one of the party's most powerful members would strike a significant blow.
"McConnell is the face of congressional Republicans," said Zelizer, "And with the state of the party the way it is, it's the minority leader who can suffer."
Kentucky may provide an early hint of how the evening is going because its polls close at 6 p.m. EST.
"If Lunsford can knock off the minority leader, well, these kind of victories are always important for the opposition party," said Zelizer.
When Republican Sen. Ted Stevens was found guilty last week on seven felony counts of making false statements in connection with taking money and other favors from supporters, it made the race with Democratic challenger Mark Begich even more of a toss-up.
But political experts say that even with a political scandal, this race could still go either way.
"One thing that happens when a candidate is in a scandal is that people vote for them because they're seen as an underdog," said Zelizer.
"People could try to defend the state -- between [Republican vice presidential nominee Sarah] Palin and Stevens," said Zelizer.
But Zelizer concedes that because the scandal is at its final stages and "guilty is part of the headline," Republicans may be unable to defend.
But that didn't keep Stevens from trying.
On the eve of Election Day the senator appeared in an infomercial on more than a half-dozen Alaska television stations in an attempt to rally last-minute support.
The two-minute ads showed Stevens telling the people of Alaska: "My Future is in God's hands. Alaska's future is in yours."
We'll likely know who the nation's next president will be by Wednesday morning, but the same is not necessarily true for the next senator from Georgia.
The race in Georgia between incumbent Republican Sen. Saxby Chambliss and Democrat Jim Martin looks increasingly likely to drag on past Election Day.
With third-party Libertarian candidate Allen Buckley pulling votes away from both Chambliss and Martin, it's possible that neither the Democrat nor the Republican will achieve the 50 percent of the vote that is required for victory under Georgia law, stretching the race into a Dec. 2 run-off on and possibly leaving Democrats teetering around the 60 Senate seat mark for nearly a month.
While Obama is not expected to capture Georgia's 15 electoral votes, a recent CNN/Time/ORC poll has him trailing McCain by just five percentage points, 52-47. An overwhelming number of African American voters have turned out to vote early in the state, a result of the Democratic nominees' surging popularity.
"This is a Southern area where Obama's success and excitement could at least close the gap," said Zelizer.
The economy has been another huge issue in Georgia, where Chambliss has been criticized for his support of the $700 billion financial bailout plan that Congress approved last month.
Minnesota is another state where a third-party candidate is complicating the issue. Independent Party candidate Dean Barkley isn't making things easy for Republican incumbent Sen. Norm Coleman and comedian-turned-Democratic challenger Al Franken (yes, that Al Franken).
But Minnesota does not have a 50 percent rule similar to Georgia's, so either Coleman or Franken could win the seat with less that 40 percent of the vote.
Barkley, according to political experts, has been successful in garnering support from voters who are tired of the Coleman and Franken horserace.
"Barkley is sort of the opt out choice for people who are sick of Coleman and Franken," said Duffy. "Watch Barkley's number all night -- I'd expect whoever wins might only win with 38 or 39 percent of the vote."
Duffy adds that while Obama has been doing well in Minnesota -- the Star Tribune/PSRA poll shows him leading McCain 53-42 -- voters in the state have been known to split their tickets.
"I wouldn't be surprised to see Coleman do well even if Obama is doing well," said Duffy.
Zelizer said that while Coleman has remained popular during his tenure in the Senate, he has suffered from "the implosion of the GOP."
The latest poll by the Star Tribune/PSRA on Oct. 31 has Franken leading Coleman 42-38
"Like Dole in North Carolina, Coleman is being dragged down by a party he is often at odds with," Zelizer said.
Sen. John Sununu's father once helped run the White House, and the Sununu family is as prominent as you get in state Republican quarters. But Sununu has been behind for most of his race against Democratic challenger Jeanne Shaheen, who lost to Sununu six years ago by just four percentage points.
In this year's race, the most recent AP/GfK poll has Shaheen leading Sununu 47-41.
David King, a public policy lecturer at the Harvard Kennedy School of Public Policy in Massachusetts, said that both Sununu and Shaheen have been using the same tactic of tying the other to President Bush.
Sununu repeatedly points out that Shaheen has supported many of Bush's policies. But an association with Bush to some degree, said King, may actually help the Democrats.
"To moderate conservatives it has even made Shaheen seem more acceptable," said King.
King added that Sununu's popularity in the state and his strong campaigning might push him over the top again.
Zelizer said that despite Sununu's "name-brand" in the state, the unpopularity of McCain and the Bush administration in the Northeast is crippling the him.
"A loss for Sununu would be a lost Northeastern Republican, and there the Democrats are really benefiting," said Zelizer.
The latest AP/GfK poll on Oct. 26 had Shaheen leading Sununu 47-41.