In his feeble, distracted debate performance against Mitt Romney, President Obama all but ignored the major Democratic lines of attack against the Republican nominee, forcing Joe Biden to consider an effort to renew those forgotten narratives when the vice-presidential candidates face one another Thursday night.

Team Obama has spent hundreds of millions of dollars (and placed nearly three times the number of attack ads as the Romney campaign) to advance three core criticisms of the GOP nominee:

• He is a privileged plutocrat who can’t relate to ordinary people. 
• He is an unprincipled flip-flopper who switches positions for political advantage.
• He’s a shady Wall Streeter whose still-secret tax returns undoubtedly conceal damning revelations of job-killing abuses.

The president of the United States never probed any of these perceived vulnerabilities in the debate, keeping their exchanges relatively high-minded, occasionally professorial, and, to a surprising extent, nonconfrontational. The Obama inner circle—or, very possibly, the president himself—apparently decided it might look demeaning, undignified, nasty, and unpresidential to slam Romney’s character in the rock-’em, sock-’em, go-for-the jugular style of notorious TV ads from various pro-Obama super PACs. As a result, their candidate fought the first debate on Romney’s battlefield of choice, talking about the hard-times economy and Mitt’s proposed solutions rather than focusing any attention at all on the GOP nominee’s alleged character flaws.

With a perceived shift in momentum in the overall campaign and the universal conclusion that Romney prevailed in the first televised encounter of the debate season, Joe Biden will feel considerable pressure to take up the cudgels and go after the GOP-ticket hammer and claw when he takes on Paul Ryan on Oct. 11.

The Obama high command may well push the vice president to ignore or patronize the youthful Wisconsin congressman standing on the stage beside him and instead concentrate his fire on the absent presidential nominee, who, of course, won’t be able to defend himself. Biden could even try a few lines praising Representative Ryan by contrasting him with the evil Romney. For instance, “I like Paul Ryan; he’s a fine young man,” the avuncular veep could intone. “And I think he’s sincere about the extremist positions he holds—unlike his running mate, Mitt Romney, who’s not sincere about anything and changes his positions more often than he changes his millionaire’s silk underwear.”

A full-throated Biden attack on Romney (not Ryan), no matter how tasteless or baseless, would bring the Democrats several advantages:

First, it would conform to a traditional function of vice presidents and vice-presidential candidates, who often operate as “hatchet men” and savage the opposition while their senior partners remain above the fray to preserve their nice-guy reputations. Richard Nixon performed such service for Dwight Eisenhower, as did Spiro Agnew for Nixon and Bob Dole when chosen as running mate for the unsuccessful ’76 campaign of Gerald Ford. Nobody cares if a veep contender comes across as particularly likable: Dick Cheney helped George W. Bush win two difficult campaigns, but he won few points for his warm, fuzzy, cuddly presentations.

Moreover, if Biden comes into the debate with an angry assault on “Mitt the Twit”—the arrogant, Richie Rich, flip-flopping opportunist who made his pile by sending American jobs overseas and feels only contempt for 47 percent of Americans he dismisses as “victims,” the vice president could force Paul Ryan into an intensely uncomfortable position.

If Ryan tries to defend the GOP nominee, he risks looking apologetic and even evasive, raising questions about why Romney hasn’t been more effective and definitive in defending himself. If, on the other hand, Ryan tells Biden that he’s not there to talk about Mitt’s personality or business history but prefers to discuss the pressing issues (where Ryan’s experience and intelligence could trump Biden’s), it looks as if he’s dodging a fight and refusing to answer ugly charges against Romney because there’s no easy way to answer them.

Either way, it takes the focus away from Ryan—who remains something of an impressive but imprecise blur in the public mind—and it pushes the Romney-Ryan ticket into an awkward defensive posture.

Had Obama launched such nasty attacks with Romney himself standing just a few feet from him, it could have offended many observers as “unpresidential,” but since the vice-president position has traditionally been viewed as something of a joke, no holder of that less-than-august office need worry about acting “un–vice presidential.”

Two-term veep John Nance “Cactus Jack” Garner famously said the vice presidency “isn’t worth a bucket of warm spit,” though his actual quote (before historical cleanup) actually referenced urine rather than saliva.

With that in mind, it could make some sense for Biden to hurl that bucket of liquid waste at the currently surging opposition and to risk everything with an obnoxious, let-’er-rip assault. Since both Joltin’ Joe and the office he holds have already become punchlines, he may decide that he might as well throw a few real punches.