Mr. Biden called Mr. Danforth’s complaint an insult to the Senate.

“I have a higher opinion of the ability of my colleagues to do what’s right than, apparently, the senator from Missouri does,” he said.

Mr. Biden’s approach to the Bork nomination was a legislative and political success, one he experienced as personal redemption after his presidential candidacy crumbled. It brought to maturity the strategic instincts that defined him in subsequent battles — including his contested stewardship of the Thomas hearings — and that shape his candidacy today.

The fate of Mr. Biden’s campaign, and perhaps a future presidency, may hinge on whether that version of leadership, defined by collegiality and adherence to procedure, can inspire Democrats and coax cooperation from Republicans. In the presidential race, there is no Ted Kennedy to sound a trumpet for the left while Mr. Biden plays a methodical inside game. And there are no Republicans to be found in the Senate like Specter, who eventually, at Mr. Biden’s urging, quit the G.O.P. to become a Democrat before his death in 2012.

Still, Mr. Gitenstein said he had encouraged the former vice president to draw public attention to his role in the 1987 court fight. The defeat of Robert Bork averted a solidly conservative majority, handing the court’s decisive seat to the more pliant Anthony M. Kennedy, who became a decisive figure in a generation’s worth of eclectic rulings on subjects from campaign finance and union rights to abortion and the legal definition of marriage.

“I don’t think he or anyone else makes enough of the fact that, but for Biden, Roe would be dead 30 years ago, and, but for Biden, we wouldn’t have the gay marriage decision,” Mr. Gitenstein said. “I’ve talked to him about it. He’s got so much on his platter.”

Mr. DeConcini, who at 82 is a supporter of Mr. Biden’s campaign, said he hoped a strategy of moderation could prevail again.

But he admitted to having doubts.

“I’d like to think so, I really would,” Mr. DeConcini said. “I’m just not sure.”