He has telegraphed it for months in early primary states and on Sunday talk shows, but Sen. Joseph R. Biden Jr. today formally launches his campaign for the 2008 Democratic presidential nomination.

Stressing his credentials as one of the party's leading voices on foreign policy, Biden, 64, of Delaware, vowed to "make us safe in the world" as president.

Biden is attempting a comeback 20 years after his first presidential candidacy flamed out amid accusations he plagiarized parts of his speeches and cheated in law school.

"I got back up off my back," Biden said in an interview. "I hope I established in the minds of the American public and the press that I went on to be . . . at least a significant senator dealing with the major problems America faces."

Biden, a senator for 34 years, joins a primary field dominated by Sen. Hillary Rodham Clinton of New York and Sen. Barack Obama of Illinois, who are drawing outsized media attention as the potential first female and first black presidents.

Republicans who are running for president include: Sen. John McCain of Arizona, former Massachusetts Gov. Mitt Romney; former Arkansas Gov. Mike Huckabee; and Sen. Sam Brownback of Kansas. Former New York Mayor Rudy Giuliani is considering a run.

Biden planned to file papers establishing a campaign committee today and to launch a Web site, www.JoeBiden.com, with a video statement, rather than a traditional rollout in Iowa or New Hampshire or the Senate Caucus Room. As chairman of the Senate Foreign Relations Committee, Biden is working on a nonbinding resolution opposing President Bush's plan to send 21,500 more troops to Iraq.

"I'm worried that, God forbid, we may be in the same position, only worse off 18 months from now," Biden said. He faulted Bush for what he called "recalcitrance" and an unwillingness to listen to advice from across the political spectrum.

Biden was one of the first to suggest that Iraq should be partitioned into three states along ethnic and sectarian lines to reduce violence there.

Although he is a harsh critic of the war now, Biden voted to authorize the use of force in Iraq in 2002, and, along with several other Democratic contenders who did the same, is likely to face questions from the party's influential antiwar left.

Biden said that the use-of-force resolution was designed to tighten the screws on dictator Saddam Hussein and that Bush misused it.

"I didn't have any idea of the degree of incompetence that existed in the administration," said Biden, who was first elected in 1972. "I assumed that these guys were grown-ups. They turned out to be . . . arrogant, immature and wrong. It actually took my breath away."

Biden, who was elected to his sixth term in 2002, has about $3 million in his Senate campaign account that will be transferred to his presidential committee. He has said he needs to raise about $20 million before the early primaries of 2008.

He will need it to keep up with Clinton, who had more than $14 million at the end of November, and Obama, who raised at least $7.5 million in 2006.

Biden also faces the better-known former Sen. John Edwards of North Carolina as well as former Iowa Gov. Tom Vilsack and New Mexico Gov. Bill Richardson.

"We all have different hurdles to overcome," Biden said. "Mine is to demonstrate that I can raise enough money to be competitive and to demonstrate that I can overcome these large figures that are looming out there. Theirs is to demonstrate they have the capacity to be president."

He said he would match up well with the latest stars in the Democratic firmament "once sort of the bloom is off the rose" and all the candidates face tough questioning in Iowa and New Hampshire.

"This is not going to be an election that lends itself to celebrity nor lends itself to wedge issues," Biden said, arguing that voters are serious and looking for assurances of physical and economic security from their next president.

In September 1987, Biden pulled the plug on his first presidential campaign. In addition to using passages from former British Labor leader Neil Kinnock and Robert F. Kennedy without attribution in some speeches, Biden exaggerated his academic record and, in a bizarre incident, berated a voter he thought had questioned his intelligence. (Biden later was cleared of unethical conduct by the Delaware bar.)

He said that lessons he learned had made him a better person and candidate.

"The first is that words matter, that you can't say things lightly," Biden said. "And the other thing is that for one to lose his temper is not a good thing.. . . I learned to take a punch. I learned what it's like to literally have the thing you value most in the whole world just absolutely decimated, and climb back.

"I think I am tougher, I think I am more seasoned, and I think I am more capable of dealing, you know, with tough circumstances."

Hear the Biden interview

at go.philly.com/bidenEndText

Contact staff writer Thomas Fitzgerald at 215-854-2718 or tfitzgerald@phillynews.com.