Joseph Biden, the senior senator from Delaware, is the Democratic Party’s main spokesman on international affairs; he is also a man who, on occasion, seems not to know, when sentences leave his mouth, where they are going or what they are meant to convey. Sometimes, when he thinks that he may shock or amuse his listener, he begins by stating, “I’m going to get in trouble if I say this,” or, “This is a really outrageous thing to say, but . . . ” And so when I asked Biden, as the ranking Democrat on the Senate Foreign Relations Committee, and one of John Kerry’s chief advisers on foreign policy during last year’s Presidential campaign, what advice he gave Kerry on how to convince voters that he was tough, Biden laughed and said, “I wish I could tell you. I wish I could tell you.” Then he told me.

At sixty-two, Biden has a cheerful vanity and an exuberant restlessness that make him seem far younger. Since the election, he has become a leader of a modest-sized faction—“the national-security Democrats,” in the words of Richard Holbrooke, an ambassador to the United Nations under President Clinton—that includes the most hawkish members in the Democratic Party. Among them are Senator Hillary Rodham Clinton, the former Vice-Presidential candidate John Edwards, Senator Evan Bayh, of Indiana, and Governor Bill Richardson, of New Mexico, along with a number of Clinton Administration foreign-policy officials, now in exile at think tanks scattered about Washington.

Biden can be eloquent in defense of his party, and in his criticism of President Bush, but his friends worry that his verbal indiscipline will sabotage any chance he might have to win the Democratic Presidential nomination in 2008. (Biden is an interested, but undeclared, candidate.) On the question of Kerry’s mettle in the last campaign, for instance, Biden told me a story that was both entertaining and illuminating but did not capture the matter with complete accuracy.

On October 29th, Biden said, he was campaigning for Kerry in Pennsylvania, the state in which he was born, when he heard, on the radio, that Osama bin Laden had issued a videotape in which he belittled Bush and promised to continue to “bleed” America. Biden nearly panicked when he heard about the tape, he said, because he worried that Kerry’s reaction might seem tepid or petty. His advice to Kerry throughout the campaign—which, he complained, went unheeded much of the time—was to harden his message, to focus, as Bush was doing, on terrorism alone: to sound, in short, more like the President and less like a Democratic senator from Massachusetts.

“I’m listening to the radio,” Biden said. “ ‘Today’ ”—here he adopted a radio announcer’s voice—“ ‘the President of the U.S. said dah-dah, dah-dah, dah-dah, and he said he’s sure Senator Kerry agrees with him. Senator Kerry, unable to resist a dig’—that’s what the announcer said, that was the phrase—‘said today had we acted’—I’m paraphrasing—‘had we acted properly in Tora Bora, we wouldn’t have this problem.’ ”

Biden continued, “I’m on the phone, I e-mail, I say, ‘John, please, say three things: “How dare bin Laden speak of our President this way.” No. 2, “I know how to deal with preventing another 9/11.” No. 3, “Kill him.” ’ Now, that’s harsh. Kerry needed to be harsh. And it was—Jesus Christ.” Here Biden threw up his hands. “He didn’t make any of it. Let’s get it straight. None of it. None of those three points were made.”

This was not quite the case. In Kerry’s first comment, made during an interview with a Milwaukee television station, he criticized Bush for missing an opportunity to kill bin Laden at Tora Bora, as he often had during the campaign. But, not long after that, Kerry spoke to the press, saying, “As Americans, we are absolutely united in our determination to hunt down and destroy Osama bin Laden and the terrorists. They’re barbarians, and I will stop at absolutely nothing to hunt down, capture, or kill the terrorists wherever they are, whatever it takes, period.”

Biden, apparently, did not actually reach Kerry until that night, so Kerry made this statement without Biden’s help. In any case, Biden failed to recount the dénouement; leaving it out better served the point of his story, which concerned the troubles that faced the Kerry campaign and, by extension, the Democratic Party—a party that Biden hopes to see revived. It was then, Biden went on, that he realized Kerry would lose the election.

“That night, I got off that trip, from Scranton, I got off the plane, Wilmington airport, only private aircraft, get off, pick up a phone, call a local place called the Charcoal Pit before it closes. They have great steak sandwiches and a milkshake. Triple-thick milkshake. And I hadn’t eaten. I’m going to pass it on the way home. They’re literally sweeping the floors. A woman, overweight, forty years old, a little unkempt, had a tooth missing in the side, not in the front”—he showed his flashing white teeth, to demonstrate—“walks up to me to give me my steak sandwich. ‘Senator Biden, I’m so glad you’re here. I’ve got a problem.’ And I take out a piece of paper, maybe Social Security for her mother, and she said, ‘I heard you’re for Kerry.’ And she said, ‘You’re so strong and he’s so weak.’ ”

Biden looked at me, to make sure I understood what he seemed to think was a point of considerable nuance. “I’m gonna tell you why I’m going to vote for someone,” he said, addressing the woman of the story. “Look, you’re working here tonight. If the Republicans have their way, you won’t get paid overtime. When you stay here tonight, you’re already closed. Besides that, what they want to do with your health care.” Then he quoted what the woman had replied: “But you’re so strong, and he’s so weak. And President Bush—he seems strong.”

In the peculiar vocabulary of Washington, Democrats who wish to be thought of as preoccupied with defense issues—and no one seeking elected office wants to be thought of as anything but firm on matters of national security—are frequently described by their staffs as “muscular,” or “robust,” or “hard-nosed,” or “forward-leaning.” Republicans do not often use words like these when describing their leaders, because the muscularity of the President and his partisans is assumed, just as Democrats don’t find it necessary to refer to themselves as “compassionate.”

The opposite of “muscular” is, of course, “weak,” and it was, for a moment, surprising to hear Biden suggest—even in his marginally sly, I’m-just-repeating-what-someone-told-me sort of way—that Kerry was weak. After all, he calls Kerry a friend. (The reverse is also true: Kerry told me last week, after I briefly sketched for him Biden’s critique, that he “loves” Biden and “welcomes his advice.”)

But Biden and Kerry are also rivals—for primacy among the forty-four members of the Democratic caucus in the Senate and, presumably, for the Party’s Presidential nomination in 2008 as well. “Weak” is a powerful epithet among the Democrats, who are still staggering as a result of last year’s election, which, polls suggest, seems to have turned less on such issues as gay marriage and abortion than on the perception that Kerry and the Democrats were not quite up to the task of defending the nation. And most Democrats I’ve spoken to in the past month have said that this issue will be a determining factor in the next election, too. To paint a rival as weak on defense is to ruin his chance for national office. As Senator Bayh put it, “If the American people don’t trust us with their lives, they’re unlikely to trust us with much else.”