President Bush (search) and Sen. John Kerry (search) planned to crisscross the country Sunday to rally voters in key states as a new FOX News/Opinion Dynamics poll suggested a close race was growing even closer.

The poll, conducted Oct. 28-29, shows Bush has the support of 47 percent of likely voters, down from 50 percent on Oct. 27-28, while support for Kerry has remained at 45 percent. Independent Ralph Nader is favored by 1 percent in the latest poll.

It is unclear what impact the release of a new videotape from Usama bin Laden (search) has had on support for either candidate. Half of the 1,200 Americans sampled were polled before the new video from the Al Qaeda leader.

The poll also was conducted at the height of the flap over what happened to 377 tons of explosives from an Iraqi military facility around the time of the U.S.-war against Saddam Hussein (search) last year.

Bush's lead is well within the margin of error, which means the rivals are effectively running even, and among registered voters the two are tied at 46 percent.

While self-identified independents picked Bush over Kerry 44 percent to 41 percent, more Bush supporters said they were open to changing their minds — 12 percent to Kerry's 6 percent. Ninety-two percent of Kerry supporters said their votes were definite, whereas 87 percent of Bush voters said they couldn't be swayed.

On Sunday, Bush planned to cover Florida, with campaign stops in Miami, Tampa and Gainesville, Fla. He was then slated to appear in Cincinnati, where he'll spend the night. Kerry was scheduled to hit Dayton, Ohio, Manchester, N.H., and Tampa, Fla., before overnighting in Orlando.

Terror Shadows Campaigns

Although it's influence on voters is still unclear, the surfacing of the bin Laden tape certainly colored the rhetoric of both camps Saturday.

"It's very helpful to the president," contended Bush ally Sen. John McCain (search), R-Ariz., although the president didn't mention the menacing new message from bin Laden at his first campaign stops on a four-state, 14-hour swing.

Rather, Bush declared, "The terrorists who killed thousands of innocent people are still dangerous and they are determined."

Campaigning 25 miles from the president in eastern Wisconsin, Kerry responded to bin Laden's re-emergence with his months-old criticism of Bush's post-Sept. 11 tactics in Afghanistan, the terrorist mastermind's once and perhaps current home.

"It was wrong to divert our forces from Afghanistan so that we could rush to war in Iraq without a plan to win the peace," said the Democratic challenger. "It was wrong to outsource the job" of capturing bin Laden to local warlords.

Click here for Sunday's edition of FOXNews.com's daily campaign digest, Trail Tales.

The two candidates responded to the bin Laden tape in ways reflecting their long-held campaign strategies.

At his first stop in GOP-leaning western Michigan, the president raised the stakes in the election while reminding voters of the 2001 attacks. "Americans go to the polls at a time of war and ongoing threats unlike any we have faced before," Bush said.

In response to the videotape, the Bush administration warned state and local officials that the tape may be intended to promote or signal an attack on the United States.

Bush brushed aside questions about whether bin Laden was trying to influence Tuesday's election.

"He will not be successful if he is," Bush told Cleveland television station WKYC, in an interview conducted aboard Air Force One. "The American people will not be influenced or intimidated by an enemy of the people."

Kerry has tried to tap deep anti-war sentiment within the ranks of the Democratic Party while assuring swing voters that he would keep them safe. The decorated Vietnam War veteran pledged anew to "destroy, capture, kill Usama bin Laden and all of the terrorists."

With a touch of swagger, Kerry began one sentence by saying, "When I am president," and pledged to provide "leadership and hope" to U.S. troops seeking a quick return home from Iraq.

After his Appleton rally, Kerry handed out campaign literature to volunteers knocking on doors in the battleground state.

With up to 40 states already in the Kerry or Bush camps, the race is concentrated in closely fought Florida, Ohio, Pennsylvania, Wisconsin, Iowa, Minnesota, New Mexico and Nevada. Another six to 12 states could come into play before their unconventional campaigns draw to a close.

Throughout the battlegrounds, Kerry's mostly paid army of organizers were pitted against Bush's largely volunteer-driven team to get supporters to the polls Tuesday. It's too late for some: Early voting mushroomed this year and, in Florida alone, nearly 2 million voters have already cast ballots.

"It looks like the All-American tradition of voting on Election Day is going out the window," said Fred D. Galey, elections supervisor in Brevard County.

In Maine, a state Bush expects to lose to Kerry, the Democrat poured last-minute money into a Social Security ad aimed at elderly voters in the north. Unlike most states which have a winner-take-all system, Maine awards two of its four electoral votes based on congressional district votes.

Hawaii's four electoral votes drew Democrat Al Gore (search) to the islands he won in 2000. Wearing a green-and-red flower lei, the former vice president tried to shore up Kerry's campaign in the Democratic bastion.

Rock musician Jon Bon Jovi and actor Ashton Kutcher campaigned with Kerry in Iowa, another Gore-won state looking shaky for Democrats. "You have the power to give America a fresh start," Kerry said, borrowing the campaign slogan of former Democratic rival Howard Dean.

Kerry's wife, Teresa Heinz Kerry (search), meanwhile, joined former President Clinton (search) on the stump in Santa Fe, N.M. Clinton was thinner but sounded strong after quadruple bypass heart surgery seven weeks ago. "This is part of my rehabilitation therapy," he said to cheers. "You're good for my heart."

The congressional races did not lack for intensity, an unexpectedly close Senate campaign in Kentucky among them. "I think we've all broken the Ten Commandments," said Sen. Jim Bunning, accused by his Democratic rival of violating two of them. Dan Mongiardo made his charge after Republicans suggested he is gay, which he denied.

In a presidential race this close, both sides are on the alert for below-the-radar nastiness. Democrats said a bogus letter was circulating in South Carolina, threatening the arrest of voters who had outstanding parking tickets or failed to pay child support.

Vice President Dick Cheney (search) told Pennsylvania Republicans that the bin Laden tape is "a reminder that we are engaged in a global war on terror."

McCain, who has repeatedly campaigned on Bush's behalf, said the terrorists' videotape "focuses America's attention on the war on terrorism. I'm not sure if it was intentional or not, but I think it does have an effect," he said.

Kerry spokesman, Mike McCurry, rejected Republican assertions that the Democrat was playing politics with the bin Laden tape.

The Associated Press contributed to this report.