As President Obama and Mitt Romney head into their rematch Tuesday night, Vice President Joe Biden can claim to have done what he could to calm the distress of fellow Democrats in the wake of Mr. Obama's sub-par performance in the first presidential debate.

Mr. Biden's aggressive, even at times blunt, manner in his contentious confrontation with Republican Paul Ryan may have been a bit too hot for neutral or undecided voters. But it clearly aimed at the Romney vulnerabilities that Mr. Obama had failed to address in that first encounter. Mr. Biden gave fellow Democrats grounds to believe, or hope, that he had put the Obama campaign back on track.

Particularly, the emotional self-styled champion of blue-collar, middle-class America poured on a heavy dose of what Republicans deride as class warfare against Messrs. Ryan and Romney, repeatedly arguing against their proposals for deep cuts in the nation's social safety net.

Mr. Biden took up President Obama's less fiery allegation that the Republican playbook would continue the tax cuts for the wealthiest Americans of the George W. Bush era, charging that these cuts would come at the expense of a vanishing middle class. In so doing, Mr. Biden seemed at times to let his ire get the better of him, scowling in the way Al Gore let sighs and raised eyebrows convey contempt toward Mr. Bush in one of their 2000 debates.

How Mr. Biden's display played with independent and undecided voters is uncertain, but it touched all the right buttons with fellow Democrats who were depressed by Mr. Obama's seemingly lackluster first debate against Mr. Romney. Perhaps the most pointed exchange spotlighted Mr. Biden's repeated and firm insistence that American combat forces will be out of Afghanistan by 2014.

It is an Obama commitment urged on him by Mr. Biden as far back as 2009 when the president acquiesced to his generals' call for an American troop surge of the sort Mr. Bush had ordered in Iraq. In the closed-door debates on it, Mr. Biden argued strongly and effectively that the surge be accompanied by a committed timeline to end the U.S. combat mission in Afghanistan after more than a decade.

Mr. Ryan responded with the assurance that he too wanted the American forces out, but only with the old Bush caveat that their removal be subject to the wishes of the generals on the ground. Mr. Biden heatedly noted that the Joint Chiefs of Staff agreed with the 2014 deadline at the time -- "period." To a war-weary nation, Mr. Biden was on the side of public opinion in his insistence.

Mr. Ryan otherwise turned in a predictably self-assured and statistics-laden attack on the Obama administration still struggling after four years to lift the country from the Great Recession. He showed little of the uncertainty that might have been expected from a first-time debater on the national stage except on the issue of abortion. He was more categorical than Mr. Romney in his declaration of opposition but said essentially he would accept Mr. Romney's pro-life stance as part of the Republican ticket.

Vice-presidential debates have always been sideshows to the main event. This one was little different other than the opportunity it gave Mr. Biden to throw Mr. Obama a lifeline, which he did. Now it will be up to the president himself in Tuesday's Obama-Romney rematch in a town-meeting format with questions from the live audience and online watchers.

The buildup for this second presidential debate may well produce a record viewership, and Mr. Obama has already acknowledged he needs to step up his engagement with Mr. Romney. That suggests this time around he will follow Mr. Biden's lead of going more on the offensive, with a particular challenge that his celebrated coolness be retained without coming off as either aloof or arrogant.

These town-meeting formats have had a way of showing more personal sides of candidates, or lack thereof, with an opportunity to engage live voters on camera. Bill Clinton in 1992 and 1996 made the most of it by visibly demonstrating empathy. Neither Mr. Obama nor Mr. Romney has ever been afforded high marks in that department. It should make for good television, if not for clarifying their sharpest differences on how each will strive to cure the ailing national economy.

Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is "Joe Biden: A Life of Trial and Redemption" (William Morrow). His email is juleswitcover@comcast.net.