(CNN) -- As they enter their final day of campaigning before Election Day, Sen. John McCain is trying to swing undecided voters in key battleground states, while Sen. Barack Obama is staying on the offensive by campaigning in territory that is usually safely Republican.
In addition, both campaigns are ratcheting up their get-out-the-vote efforts, as election officials predict record turnouts -- and long lines -- on Tuesday.
McCain on Monday hopes he can shift enough voters in a handful of critical states to give him enough votes to pull a come-from-behind victory.
He has an uphill climb. There are few undecided voters left, and McCain will have to sway most of them for him to overcome Obama's lead. The latest national CNN poll of polls has Obama ahead of McCain 51 percent to 44 percent, with 5 percent undecided. iReport.com: Still undecided? What gives?
McCain has also lost ground to Obama in the race for electoral votes and needs to win a number of battleground states if he is to deny Obama the White House. Predict the outcome with the Electoral Map calculator
Going into Election Day, CNN estimates that Obama will win 291 electoral votes while McCain will win 157, with 90 electoral votes up for grabs. A candidate needs 270 electoral votes to win the presidency.
On Monday morning, McCain began a seven-state blitz with a rally in Tampa, Florida. He then heads to Tennessee, Pennsylvania, Indiana, New Mexico and Nevada. McCain ends the day in his home state of Arizona. Watch how the candidates are making the final push »
McCain's campaign manager, Rick Davis, announced Monday that McCain would campaign in Colorado and New Mexico on Tuesday.
Except for Tennessee and Arizona, McCain either trails or is tied in the states he is visiting, according to recent polling.
Davis said that victories in the three Western battleground states Tuesday could help McCain overcome potential losses in Virginia and Florida.
"If we can win Nevada, Colorado and New Mexico, all of a sudden we've got a new pathway to victory," he said. "Those weren't even on the list three weeks ago."
Putting Pennsylvania in the Republican column Tuesday night is especially critical to the Republican effort, as there are few paths McCain can take to get to the 270 electoral votes needed to win the election without Pennsylvania's 21 electoral votes.
Turning Pennsylvania from blue to red may be difficult for McCain. CNN's poll of polls calculated Monday shows Obama leading McCain 51 percent to 43 percent in the state, with 6 percent unsure. The McCain campaign, however, says that their own polling suggests that the Pennsylvania race is tighter than published polls suggest. iReport.com: 50-year-old first-time Pennsylvania voter shares his motivation
McCain might be able to pull it off, however, by emphasizing his conservative message to independent voters, in Pennsylvania and the other battleground states, who are worried what Democrats would do if they controlled both Congress and the White House. Watch the last push in Ohio »
"McCain's got to run the table on Tuesday night to really stay in this, or flip Pennsylvania," said John Avlon, author of "Independent Nation." "McCain's argument about the unified-control Congress -- what the liberal super-majority would do -- is resonating with independents ... but he's got a lot of ground to make up."
In a sign that he hopes not only to win the election Tuesday night but also, possibly, transform the political landscape, Obama is also starting the day in Florida, a state President Bush won in 2000 and 2004, with a rally in Jacksonville. CNN's latest polls of polls shows Obama with a slight lead over McCain in Florida, 48 percent to 46 percent, with 6 percent unsure. Watch whether Obama can close the deal »
The Illinois Democrat then heads to two other states that Bush won but where he is leading: North Carolina and Virginia. CNN's poll of polls has Obama leading McCain by 1 point in North Carolina, 49 percent to 48 percent, with 3 percent unsure. In Virginia, Obama is leading McCain 50 percent to 45 percent, with 5 percent unsure, according to the latest CNN poll of polls there.
Besides making last-minute pitches to undecided voters, both campaigns are ramping up their efforts to get their supporters to the polls.
Unlike previous years, the Democrats' efforts to get their supporters to the polls are much more organized than the Republicans', said Ed Rollins, a Republican strategist. Watch an analysis of how the candidates will spend the final hours »
"We have always won the early efforts. ... The Democrats have beat us at our own game more severely than ever dreamed possible," said Rollins, who served as President Ronald Reagan's political director. "They've gone out, they have intensity. People feel a real part of this process. People are willing to stand in line whether two weeks ago or tomorrow. I think voters are going to vote."
The Republicans, in comparison, "look like the party of the telegraph in this election," Avlon said.
"They're not as tech savvy or getting out the vote as much. On the ground game, in addition to all the momentum Obama has got, the ground game could prove decisive," he said.
While enthusiasm among Democrats is high, Angela Burt-Murray, the editor of Essence magazine, said Democrats are worried that problems at the polls or efforts to suppress the vote could lower the number of voters who turn out for Obama.
Burt-Murray noted that one flier circulating in an African-American community in Richmond, Virginia, falsely told voters they could vote on Wednesday, November 5, due to the expected long lines on Election Day. iReport.com: Long lines? Share video, photos
"There is certainly a lot of passion out there right now for the Obama campaign. But there are also significant challenges they're facing," she said.
CNN's Anastasia Diakides contributed to this report.