Barack Obama and John McCain are chasing each other and the presidency across a brace of battleground states as the race for the White House enters a furious 24-hour dash to tomorrow's voting.

Democratic nominee Obama will campaign today and tomorrow in four states that went Republican in 2004 and are up for grabs this year: Florida, North Carolina, Virginia and Indiana.

Republican candidate McCain will blitz across six states — Florida, Virginia, Pennsylvania, Indiana, New Mexico and Nevada — before finishing up in his home state of Arizona. On Election Day he'll travel to Colorado and return to New Mexico.

McCain is vowing to "hold the line on taxes" and cut government spending. He is telling supporters to ignore polls showing him trailing — and pointing to signs of a tightening race in Pennsylvania, which hasn't voted Republican in a presidential contest since 1988.

"Nothing is inevitable here," the 72-year-old Arizona senator said yesterday at a rally of about 2,000 people at the University of Scranton, his second event of the day in the state. "We never give up. We never quit."

Obama, 47, is seeking to tie McCain ever more firmly to President George W. Bush, calling him a "sidekick" of the Republican incumbent.

"The last thing we can afford is four more years of the same old tired, stale, old economic theories," Obama said yesterday at a rally of 60,000 supporters in front of the state Capitol in Columbus, Ohio. Later in the day, the Illinois senator appeared with rock singer Bruce Springsteen in Cleveland.

McCain's emphasis on Pennsylvania reflected the reality that Obama is running so competitively in as many as a dozen states that voted Republican in the last presidential election. McCain probably has to win a traditionally Democratic state to have a chance at reaching the 270 electoral votes needed to claim the presidency. Pennsylvania is the only choice.

"The most important state to watch right now is Pennsylvania," McCain's campaign manager, Rick Davis, said yesterday on the "Fox News Sunday" program.

Several recent polls have shown McCain narrowing Obama's lead in Pennsylvania. For example, a Muhlenberg College survey taken Oct. 29 through Nov. 2 showed Obama ahead by six percentage points; an Oct. 23-27 survey by the same pollster had Obama ahead by 12 percentage points. Still, Obama's lead is outside most polls' margin of error, giving him a clear lead.

Obama's effort to win neighboring Ohio is a reflection of that state's importance: no Republican has ever won the White House without prevailing there. The Columbus Dispatch's final poll showed him leading 52 percent to 46 percent. An average of five polls taken in the last week shows Obama with a four percentage point lead in Ohio, according to the Web site realclearpolitics.com.

Obama also held an advantage in other contested states, including Virginia, New Mexico, Colorado and Nevada. Polls show the two candidates in a close fight for Indiana, Florida, North Carolina and North Dakota, all of which McCain will need to compile the 270 Electoral College votes required to win the White House.

In Indiana, a state that hasn't backed a Democratic presidential nominee since 1964, Obama and McCain were tied at 47 percent in a survey of 900 likely voters taken Oct. 27-29 by the Downs Center for Indiana Politics at Indiana University- Purdue University Fort Wayne.

Obama's inroads into Republican states are reflected in national polls, which show him holding a steady lead over McCain. Obama is also bringing out huge crowds to his campaign rallies. In the past week he's drawn over 500,000 people to his events, numbers rarely seen in American politics.

The Web site Realclearpolitics.com showed Obama holding an average lead in national polls of just over 6 percentage points.

Still, McCain's aides claimed momentum. Davis said the election was "moving very quickly" in McCain's direction. "We're in for a slam-bang finish," Davis said. "John McCain may be the greatest closer politician of all time."

Obama aides David Axelrod and David Plouffe dismissed that argument and said McCain was being forced to defend a host of states Bush won in 2004 that are now in play.

Axelrod said on ABC's "This Week" show that victories in those states would be important both for winning the election and fulfilling Obama's goal to "get past this red state-blue state kind of paradigm that we've been locked into."

The vice-presidential candidates will also be busy today. McCain running mate Alaska Governor Sarah Palin will appear in Ohio, Missouri, Iowa, Colorado, Nevada and Alaska, while Democrat Joe Biden, a Delaware senator, will stump in Missouri, Ohio and Pennsylvania.

While the two presidential candidates mostly repeated familiar arguments yesterday, Palin opened a new line of attack in Ohio's southeastern coal region. She seized on a January recording of Obama telling the San Francisco Chronicle newspaper that his cap-and-trade energy proposal would "bankrupt" those building coal-fired power plants, she said in Marietta.

Ohio's governor, Democrat Ted Strickland, called Palin's charge a "last-minute, desperate distortion" of Obama's record.

Outside groups also stepped up attacks on Obama.

A group called the National Republican Trust Political Action Committee is running a 30-second ad tying Obama to his former pastor Reverend Jeremiah Wright. It's a topic the McCain campaign has avoided out of concern it would be seen as playing the race card.

"For 20 years Barack Obama followed a preacher of hate and said nothing," the ad says. "Barack Obama. Too radical. Too risky," it says.

Obama senior adviser Anita Dunn said the ads won't make a difference and may backfire. "These sleazy last minute smears are what's wrong with politics and why people will vote for change on Tuesday," Dunn said.

Both campaigns are spending for a blitz of advertising and get-out-the-vote efforts, with Obama putting ads on the air in Georgia and North Dakota as well in McCain's home state of Arizona. McCain's advisers said the candidate and the Republican Party would together outspend Obama on television over the last week of the campaign by about $10 million.

While most votes still are cast on Election Day, a majority of states now allow some form of early voting and figures show almost a third of ballots in the presidential race already have been cast.