The Most Important Person You've Never Heard of in Washington's Push to Reform Wall Street

April 23, 2010 -- He might be the most important player you've never heard of in Washington's push to crack down on Wall Street.

When it comes to the biggest regulatory shakeup since the Great Depression, Sen. Ted Kaufman, D-Del., does not back the views of Wall Street or Republicans or Democrats, or even the Obama administration.

The man who served more than two decades as a top aide to Vice President Joe Biden -- and was his hand-picked choice to take over the Senate seat he vacated -- is very much his own man on the issue of the moment.

Kaufman has staked out his own position: the government should break up the country's biggest banks to make sure that no firm is ever again considered too big to fail.

"The thing I'm most focused on is too big to fail," said Kaufman in an exclusive interview with ABC News. "That trumps just about everything else. We just cannot have a financial institution that is too big to fail, meaning they have to be nursed along or bailed out by the U.S. government. That cannot happen again."

But the proposal championed by Kaufman's fellow Democrat, Senate Banking Committee chairman Chris Dodd would not break up existing big banks.

"I just don't think it'll work," Kaufman said. "I'm concerned about whether it'll work with these really big banks because they're so complex, and there are so many international connections.

"I absolutely think the world of Chris Dodd. I just have a difference of opinion," Kaufman said. "My basic view of the world is these [banks] are too big to fail, and therefore that's what I'm pushing for."

If you don't know who Ted Kaufman is, that's probably because he only became a senator last year, when Biden became vice president. And he'll be a former senator by this time next year, having ruled out running for a term in his own right.

Kaufman served as Biden's chief of staff for 22 years, and the two remainclose friends, though he hasn't always been the administration's ally.

His decision not to seek another term, he said, is not what's motivated him to become more aggressive in the push for financial reforms. Nor has it coaxed him into reflexive support for the Democrats' party line.

"There's not a single thing that I would do differently if I was running this year," he said.