With Republican contender Mitt Romney pulling alongside US President Barack Obama in polls, Thursday night’s debate between the two men’s deputies will be more aimed at gaming turnout numbers than touting policies.

The race has tilted away from the Democrats recently, putting pressure on Vice President Joe Biden to “win” Thursday and bring listless voters back to the Obama camp – or at the very least prevent another embarrassing victory for the Republican ticket that could siphon more voters away.

On the other side of the stage, Republican Paul Ryan will attempt sustain the sense of energy and enthusiasm that characterized Romney’s debate performance.

With the election less than a month away and seemingly up for grabs, any high-profile event like the debate represents a make or break opportunity for both sides, and civility may be tossed aside in the mad dash for votes. In the battle for increased turnout, each side will do its best to frighten its supporters with the prospect of the other side’s victory.

A race that seemed a near-certain victory for Democratic incumbent Barack Obama just last week was thrown wide open by a surprising debate upset last Wednesday by Republican challenger Mitt Romney. After trailing behind Obama by significant margins through September, Romney now leads by 1.5 percent in nationwide polls, according to the latest RealClearPolitics average of polls.

With his bounce in the polls, Romney’s chances to win have improved dramatically, according to New York Times elections statistician Nate Silver. Silver calculated that Romney’s chances of winning the White House rose over the past week from a meager 13.9% on October 3 to 32.1% Wednesday. Obama’s chances of winning have seen a corresponding drop of more than 18 percentage points, from 86.1% to 67.9% in the week following the debate. Romney’s position will improve further if he continues to poll at the current levels.

Gallup figures published Wednesday showed that vice presidential debates have had little effect in recent decades. The organization noted that “none of the eight vice presidential debates occurring from 1976 to 2008 appears to have meaningfully altered voter preferences.” The median change in voters’ choice for president in the wake of four out of the past five vice-presidential debates – in 1992, 1996, 2000 and 2008 – was just one percent. (Gallup did not conduct a daily tracking poll in 2004.)

However, the debate will be watched as a key indicator of the momentum and enthusiasm of the two sides. And enthusiasm may be the key to this election.

At the moment, the race is incredibly close according to polls. Obama leads in Ohio by just 0.8% and in Virginia by 0.3%, and likely needs both to win reelection. Similarly, Romney currently leads in Florida, without which he has little chance of winning the presidency, by a tenth of a percent.

In such a race, victory will depend more on turnout than on changing minds.

And when it comes to turnout, Republicans may have the advantage. According to NBC polling figures released over the weekend, Republicans have seen a spike in “highly interested voters” – those responding with a nine or 10 when asked how interested they were in the election – while Democrats saw a drop from 2008. For Republicans, the figure rose from 70% in 2008 to 79% this year, for Democrats they dropped from a 2008 high of 83% to 73% today. Engagement has also risen among seniors, who lean toward Romney, and fallen among younger voters, who are more likely to vote Obama.

If the evidence of declining excitement on the Democratic side bears out in Election Day turnout, particularly in Florida, Ohio, Virginia and every else where the margins are razor-thin, the Democratic ticket may be in more trouble than indicated by the polls.

It is this stark reality that will likely drive the debates during the last four weeks left to the campaign.

For Biden, this means that he will have to make a convincing case to Obama-leaning viewers on Thursday night that his opponent’s ticket is dangerous for America.

If recent campaign stump speeches are any indication, Biden, 70, will seek to paint the much younger Republican as an irresponsible fiscal extremist who will slash governmental funding for vital health care programs and seek to curtail women’s reproductive choices.

On the other side, Ryan, 42, will do his part to further energize his own supporters and convince them their votes are vital for a November victory. Ryan will likely focus on the Obama administration’s stimulus spending, which Biden oversaw, warning that the hundreds of billions of dollars in stimulus spending have ballooned the national debt and failed to rescue or reinvigorate the economy.