NORFOLK, Va. -- Barack Obama, hoping to build momentum heading into the Nov. 4 elections, is mounting a full-court press on television Wednesday including an interview with a prominent network anchor, a taped appearance on a comedy show and a 30-minute infomercial across most networks.
His high-profile campaigning in Florida will also include his first joint appearance on the stump with former President Bill Clinton that will likely draw national news coverage.
His Republican rival, John McCain, who is also in Florida, will try to counter some of the Obama TV blitz with an appearance on CNN's Larry King Live.
Obama's 30-minute ad will air at 8 p.m. ET on CBS, NBC and Fox at a cost of around $1 million per network. It will also run on Univision, BET, MSNBC and TV One.
The infomercial will combine Obama's "description of the challenges facing the country" with vignettes of four families he's encountered on the campaign, said his chief strategist, David Axelrod. It will also feature a live segment from an Obama rally in Florida.
Axelrod said the campaign chose a 30-minute format to distinguish the ad from other political commercials. "The airways are glutted with 30-second ads and it's hard to break through," he said.
Axelrod said the timing was aimed at influencing voters as they weigh their choice in the final days of the campaign. "Late enough to do us some good but early enough to do us some good," he said.
McCain crisscrossed the Sunshine State in an effort to rally critical support in the traditional Republican stronghold that President Bush carried twice.
"We've got to win the state of Florida, my friends," McCain told supporters at a lumber yard in Miami, noting that his campaign is "a few points down" nationally and "the pundits have written us off."
McCain's lead pollster, Bill McInturff, in a memo released by the campaign, takes issue with a flurry of polls giving Obama a notable edge in polls in key battleground states. McInturff argues that the McCain campaign is "functionally tied" across these states and says undecided voters will break heavily for the Republican candidate.
The Miami and Palm Beach rallies were billed as "Joe The Plumber" events, in reference to Ohio man and Obama critic Joe Wurzelbacher. McCain has cast Wurzelbacher as the symbol of business people who would be hurt by Obama's plan to raise taxes on those making more than $250,000.
In describing the "fundamental difference" between Obama and him, McCain said, "he thinks taxes are too low and I think spending is too high,." and suggested his rival's tax policies smack of socialism.
At a rally in Raleigh, N.C., Obama fired back at such labels.
"I don't know what's next," Obama said to laughter from the crowd. "By the end of the week, he'll be accusing me of being a secret communist because I shared my toys in kindergarten."
McCain also met former top military officers who advise him on national security issues and said afterward that Obama is not up to the job of protecting the country.
"The question is whether this is a man who has what it takes to protect America from Osama bin Laden, al-Qaeda and the other great threats in the world," McCain said. "He has given no reason to answer in the affirmative."
In an appearance in another key battleground state, McCain's running mate, Alaska Gov. Sarah Palin, delivered a policy speech in Toledo, Ohio, that called for a "clean break" from the Bush administration's energy policies, which she says relied too much on importing foreign oil.
She also criticized her home-state senator, Republican Ted Stevens, who was convicted this week on seven counts of failing to disclose gifts he received from an oil executive.
"Alaska's senior senator is not the first man to discover the hazards of getting to close to oil money interests with agenda of their own," she said.
Obama's TV blitz on Wednesday includes an interview in Raleigh, N.C., by Charlie Gibson of ABC's World News.
Later, in Florida, the Illinois Democrat planned to tape an appearance on Comedy Central's The Daily Show with Jon Stewart that will run at 11 p.m. ET.
To cap his round of TV interviews, Obama, who has provided limited news media access in recent weeks, will give interviews to Brian Williams, anchor of NBC's Nightly News and to MSNBC's Rachel Maddow.
Contributing: Kathy Kiely, in Raleigh, N.C.; David Jackson, in Miami; Douglas Stanglin, in McLean, Va.; the Associated Press