Obama tells supporters to expect more attacks to come.

WASHINGTON (AP) — Democrat Barack Obama held onto his solid lead in the polls and appeared confident of capturing the US presidency in the historic race, but steeled his supporters for a crescendo of vicious attacks in the final hours of the campaign.

With just four days to go after a marathon contest, the Obama campaign went on the offensive in several solidly Republican states Friday. Democrats announced they would air television ads in Georgia, North Dakota and even Arizona, which Republican John McCain has represented in the US Senate for 22 years.

“We are four days away from changing the United States of America,” Obama told voters Friday night in Indiana, one of about a half-dozen Republican states remain up for grabs late this election season.

The underdog McCain, meanwhile, spent a second day touring Ohio in his “Straight Talk Express” bus, and appeared with California Gov. Arnold Schwarzenegger, a fellow Republican, in a last-ditch effort to win a state critical to his hopes for victory.

No Republican has ever been elected president without winning Ohio, but McCain trails in the polls there by a wide margin.

“We’re closing, my friends, and we’re going to win in Ohio,” McCain said during a stop in the state Friday. “We’re a few points down but we’re coming back and we’re coming back strong.”

McCain’s campaign argued that he was closing the gap in the final days and that he was closer than reflected in public polling. Privately, McCain’s aides said he trailed Obama by 4 points nationwide in internal polling.

An Associated Press-Yahoo News poll of likely voters put the Democrat well ahead nationwide, 51 to 43, with a margin of error of plus or minus 3 percentage points.

The same survey gave McCain reason to hope — one in seven voters, 14 percent of the total — said they were undecided or might yet change their minds.

But McCain may be running out of time to turn the tide.

Obama, who is seeking to become the first black US president, has tapped public concern about two long-running US wars abroad and a faltering economy at home.

He has also raised hundreds of millions of dollars more than McCain for his campaign.

McCain and his supporters have fought back by accusing Obama of associating with radicals, advocating surrender in Iraq and supporting socialist economic policies.

“Sen. Obama’s economic policy is from the far left of American politics and ours is in the center,” McCain said Friday on ABC’s “Good Morning America” television program.

In Iowa, Obama accused the Republicans of practicing “slash and burn, say-anything, do-anything politics that’s calculated to divide and distract; to tear us apart instead of bringing us together.”

He said he admired a presidential candidate who said in 2000: “I will not take the low road to the highest office in this land.”

“Those words were spoken eight years ago by my opponent, John McCain,” Obama said. “But the high road didn’t lead him to the White House then, so this time, he decided to take a different route.”

Despite this, Obama later told CNN that, if he is elected, he would consider appointing McCain to “any position … where I thought he was going to be the best person for our country.”

As part of McCain’s effort to capture Ohio, McCain hosted Schwarzenegger — the former bodybuilder and actor who played the lead in the “Terminator” series of Hollywood blockbusters — at a rally in the city of Columbus Friday afternoon, where he offered to help the lanky Obama beef up his “skinny legs” and “scrawny little arms.”

“John McCain has served his country longer in a POW camp than his opponent has in the United States Senate,” the Austrian-born politician said. “I only play an action hero in the movies. John McCain is a real action hero.”

McCain’s campaign said the candidate would appear Saturday on the late-night comedy show, “Saturday Night Live.”

The satirical program has bolstered its ratings in recent months by lampooning McCain’s choice for the Republican vice presidential candidate, Alaska Gov. Sarah Palin, who is bidding to become America’s first woman vice president.

Both McCain and Obama are expected to appear at half time on a nationally televised American football game Monday night.

But nationwide appeals may matter less, in the end, than the grueling chess game of state-by-state campaigning that marks US presidential contests.

Under the US system, the president is not elected by direct popular vote nationwide. Instead, the successful candidate must win 270 out of 538 electoral votes in what amounts to a state-by-state contest. Electoral votes are allocated to each state roughly according to population.

McCain has won come-from-behind political contests before. But his campaign has struggled throughout the fall, plagued by internal bickering and divisions in the party ranks.

In an interview Thursday with National Public Radio, Lawrence Eagleburger, a former secretary of state and prominent McCain supporter, who said Palin isn’t prepared to take over as president in a crisis.

He added that she could eventually become “adequate.” He later apologized for the comments.

Palin campaigned Friday in Pennsylvania, where she charged that Obama represented the “far left wing” of the Democratic party and had an ideological commitment to raising taxes.

Obama is proposing tax increases on families making over $250,000 and individuals making over $200,000 and tax cuts for the 95 percent of workers making less than $200,000.

The Democrats’ vice presidential candidate, US Sen. Joe Biden, told a crowd in Delaware that history will judge the Bush administration harshly for failing to build a strong economy and to unite the world against global terrorism.

“The Bush legacy, the one that John McCain wants to continue, is an America where we are divided from each other, a nation divided from the world,” Biden said.

Obama planned final get-out-the-vote rallies in Nevada, Colorado and Missouri Saturday. He was scheduled to campaign in Ohio all day Sunday, including a Cleveland rally with singer Bruce Springsteen, then hit Virginia and Florida on Election Eve.

McCain had eight states on his final three-day itinerary besides the detour to New York City for “Saturday Night Live,” hosted by Obama supporter Ben Affleck. Monday’s schedule called for him to visit several states, ending with a midnight rally in his home state of Arizona where Obama was running television ads.

“We want to win everywhere,” Obama said of his decision to air the commercials in his opponent’s state.