Sen. Joe Biden at times has been the subject of an old Beltway joke about the most dangerous place in Washington -- "between (politician's name here) and a microphone."

Biden, D-Del., often has joked about the Biden caricature, now a "Saturday Night Live" parody: He's pompous, preening, bombastic, a camera-loving show-off, a loose cannon, a gaffe waiting to happen.

And this: He's emotional. That was on display for a fleeting moment during his debate with Republican Alaska Gov. Sarah Palin. Biden's voice caught in his throat as he recalled suddenly becoming a single father 36 years ago.

His first wife, Neilia, and their baby girl died in a 1972 car accident that also left his toddler sons, Beau and Hunter, in critical condition. Biden, now 65, had just been elected to the Senate a few weeks earlier.

In that debate moment, Biden "could picture Beau in bed," Biden later told Newsweek.

"But the notion that somehow, because I'm a man, I don't know what it's like to raise two kids alone, I don't know what it's like to have a child you're not sure is going to -- is going to make it -- I understand," Biden said in the debate, responding in part to Palin's assertion that as a mother she understood the nation's "kitchen table" issues.

Biden's memory of his young boy and his concern for grown son Beau, now a National Guardsman headed to Iraq, "created a lot of bundled emotions," Biden told Newsweek. "It surprised me. I was hoping nobody noticed."

About 70 million debate viewers did, the magazine noted.

By Biden's account, the family that he was raised in, and the one he has raised, dramatically shaped and rooted the man who Sen. Barack Obama has said would be a close adviser and sometimes foil.

Biden was heralded as a safe but smart choice by Obama. The media have often described him as a savvy Beltway insider who has somehow also eschewed official Washington and stayed close to his working-class roots.

Where Obama's international affairs experience is thin, Biden has developed a reputation as one of the nation's leading foreign policy experts. Biden often claims among his top accomplishments helping to bring stability to the Balkans; being a leader in the effort to end genocide in Darfur; and having become an outspoken critic of the war in Iraq after he voted for the authorization for the war.

On domestic policy, Biden prides himself on being an author or co-author of numerous crime bills, including the Violence Against Women Act, and legislation that provided for 100,000 new police officers.

Biden is a pro-choice Roman Catholic teetotaler who first ran for president in 1988 but withdrew amid a plagiarism scandal. His 2008 bid ended early, after a fifth-place finish in the Iowa caucuses.

During his long tenure in the Senate, Biden has developed a reputation as a fierce debater with a quick wit and sharp one-liners. During his own presidential campaign he memorably said all sentences spoken by former New York Mayor Rudy Giuliani contain "a noun, a verb and 9/11."

Biden also sticks his foot in his mouth. Last year he said Obama is "the first mainstream African-American [to run for president] who is articulate and bright and clean and a nice-looking guy." He immediately apologized. Obama immediately accepted.

Biden often touts his modest upbringing. He was the oldest of four children, born in Scranton, Pa. The family later moved to Delaware, where his dad became a used car dealer. Biden has often spoken of his father's failures and resilience.

"My dad -- my dad, who fell on hard times, always told me, though, 'Champ, when you get knocked down, get up. Get up,'" Biden said during his Democratic convention speech.

Biden earned a law degree at Syracuse University, and at age 29, he won in an unlikely upset over a two-term incumbent Republican.

Biden was sworn in at Beau's hospital bedside as one of the youngest senators ever. Since the accident, Biden has been a vocal Amtrak advocate and has commuted almost daily by train from Wilmington to Washington.

Three years after the accident, Biden saw a photo of a young blonde in an advertisement for a Wilmington park, according to a New York Times account. That night, he went on a blind date arranged through his brother, Frank, and he was astounded to find it was the same woman, Jill Jacobs.

She was impressed he wore a suit, the Times noted. She knew who he was -- she had voted for him in 1972.

By media accounts, Biden was unfocused and listless in the first few years after the accident, his first in the Senate. In his book, "Promises To Keep," Biden credits Jill for renewing his interest in politics and life.

They married two years later; the boys went on the honeymoon. The couple has a daughter, Ashley, born in 1981.

Jill Biden has a Ph.D. in education and is a professor at Delaware Technical Community College.

She prefers a quiet teaching career in Delaware to the Washington cocktail circuit. But still upset by George W. Bush's 2004 re-election, she prodded her husband to run. In a January interview with National Public Radio, Jill Biden recounted how she and Biden's three grown children met and then together called the senator to an emotional family meeting so they could ask him to join the race.

"Finally we decided we just have to go to dad with this, and we did," she told NPR.

Hunter Biden, 38, is a founding partner of the lobbying firm Oldaker, Biden & Belair, LLP. He is vice chairman of the Amtrak Board of Directors.

Beau Biden, 39, is Delaware's attorney general as well as an Army Guardsman. Sen. Biden spoke at a deployment ceremony for his son's unit.

"Dad, keep it short," the younger Biden told his father. "We're in formation."