Adding one more chip to the big bet he has placed on Pennsylvania, Sen. John McCain will fly into Pittsburgh for an airport rally this morning following two appearances yesterday in the eastern part of the state.

His 11th-hour appeals in this state are one part of the avalanche of calls, door-knocking and last-minute campaigning rolling across the remaining competitive states in a presidential election that could set a record for voter turnout. Mr. McCain's cross-country journey today begins in Tampa, Fla., and includes rallies in Blountville, Tenn.; Pittsburgh; Indianapolis; Roswell, N.M., and Henderson, Nev., before concluding in the city of Prescott in his home state of Arizona.

While the Republican underdog courted votes in the Philadelphia suburbs and in Scranton, yesterday, Sen. Barack Obama was concentrating on the neighboring battleground of Ohio, where he was cheered by supporters in Columbus before joining singer Bruce Springsteen for a massive outdoor rally in Cleveland. Mr. Obama's final day today is somewhat less ambitious, with rallies in Jacksonville, Fla.; Charlotte, N.C., and Manassas, Va. Then he will return to his home in Chicago to await the results.

Traveling here this morning, Mr. McCain will cross paths with Sen. Hillary Rodham Clinton, who again will ask the voters of a state that supported her in its April primary to turn out for her rival for the Democratic nomination. Details of Mrs. Clinton's planned appearance here were unavailable last night.

Former President Bill Clinton will also barnstorm the state today. In addition to an appearance in Erie, he'll make two more stops hoping to rehabilitate the campaigns of two of the few vulnerable Democratic House incumbents in a year in which their party hopes for another big gains in Congress. The former president will stump for Rep. Paul Kanjorksi, D-Luzerne, and Rep. John Murtha, D-Johnstown.

Such high-profile appearances will dominate the television news. Less visibly, the campaign's get-out-the-vote operations, the focus of months of planning and groundwork, have shifted into their intense final sprints toward Election Day tomorrow.

Mr. McCain's concentration on Pennsylvania defies polling numbers showing Mr. Obama with a substantial, though somewhat reduced lead in a state that twice narrowly eluded grasp of President Bush. Sen. John Kerry edged Mr. Bush by 144,000 votes out of the nearly 5.7 million votes cast by Pennsylvanians four years ago.

Since then, however, the Democratic registration edge in the state has nearly doubled with more than 500,000 new members of Mr. Obama's party, many signed up through the massive registration drive organized by his campaign. Democratic ranks grew by 13 percent while the number of officially Republican voters actually fell by 1 percent or about 28,000 votes. Statewide, Democrats outnumber Republicans by roughly 1.2 million, double their margin of just a year, ago.

Still, while recent polling numbers continue to favor the Democrat, they show some evidence that Mr. McCain's focus on the state has allowed him to gain ground. Earlier last month, the daily tracking poll conduced by Muhlenberg College had consistently shown Mr. Obama with a double-digit lead; now Mr. McCain has moved to within six or seven points of his rival.

"They really have gone all out here, and to some degree it has helped move the dial," said Chris Borick, the director of the Muhlenberg survey. "It has made it more competitive than some other states moving in the other direction."

In the latest Muhlenberg tracking poll, Mr. Obama had the support of 52 percent of the voters surveyed compared with 46 percent for Mr. McCain.

But Mr. Borick noted that despite some increase in Mr. McCain's support, Mr. Obama's standing in the state has remained steadily above 50 percent for weeks. Mr. Borick said that while Mr. McCain had gained some ground in the state's northeast and southwest, he appeared to have less traction in trying to overtake Mr. Obama's stronger position in the crucial Philadelphia suburbs and the adjacent Lehigh Valley

Tomorrow's results will be a partial measure of the value of personal campaigning, just as it will test the true effectiveness of the vaunted Obama ground game, which significantly outnumbers the GOP GOTV organization in offices, staffers, volunteers and other resources.

Republicans are trying to counter the apparent Democratic logistical advantage with an extensive wave of robocalls bombarding Pennsylvania and other battleground states. As both Clintons campaign in the state, one of the Republican messages capitalizes on the long Democratic primary fight with a passage from Mrs. Clinton in which, while making the case that she would be a better Democratic nominee, she favorably compared Mr. McCain's experience to Mr. Obama's.

"Sen. McCain will bring a lifetime of experience to the campaign and Senator Obama will bring a speech that he gave in 2002," the recording says.

Reacting to the call, Mrs. Clinton's office issued a statement that said: "Sen. Hillary Clinton does not approve this message, and as she criss-crosses the country, she has said time and again that the choice in this election could not be more clear. The McCain/Palin ticket offers only more of the same failed policies while the Obama/Biden ticket offers the vision, leadership and positive solutions we need. I wonder why the Republicans aren't using those words?"

Mr. McCain's rally today will be in a hangar at Atlantic Aviation, 300 Horizon Drive, in Moon. Doors to the event open at 10:45 a.m., but Mr. McCain is not expected to appear until some time after that.

The candidates will get one more crack at a national audience tonight -- and one with a disproportionate representation of Western Pennsylvanians -- when they both will appear in interviews at halftime of the "Monday Night Football" game between the Steelers and the Washington Redskins.

In his get-out-the-vote bid in Ohio yesterday, Mr. Obama took particular delight in taking note of the endorsement that Mr. McCain received Saturday from Vice President Dick Cheney, an endorsement that quickly became the subject of an Obama television commercial.

Said Mr. Obama: "[Mr. Cheney] knows that with John McCain you get a twofer: George Bush's economic policy and Dick Cheney's foreign policy -- but that's a risk we cannot afford to take. It's time for change, and that's why I'm running for president of the United States."

The Democrats have a slight lead in Ohio, which was the deciding state in 2004. No Republican presidential candidate in history has prevailed without it.

Mr. Obama's chief strategist, David Axelrod, said on ABC's "This Week" that he felt good about his candidate's chances.

"The main thing I worry about is complacency," Mr. Axelrod said. "I don't want people to hear me or anyone and assume that this campaign is over. If we are casual about this and we don't go to the polls and make our voices heard, then we could get a result that the polls don't project. And that's my concern. That's why we're hop-scotching all over the country."

In an appearance yesterday on CNN, Sen. Arlen Specter, R-Pa., said Mr. McCain might win Pennsylvania if some of this state's residents who have told pollsters they'll vote for Mr. Obama vote for Mr. McCain instead. Mr. Specter said that such behavior, if it happens, would not be evidence of the so-called "Bradley effect," in which blacks running against whites have sometimes done worse on Election Day than in late polls.

"Well, I don't like the Bradley effect categorization and I don't like the suggestion of racism," Mr. Specter said. "People are just different on polling and voting."