This evening’s presidential debate could have significant implications for downballot races across the country — a political dynamic that has Republicans hoping for a repeat performance from GOP nominee Mitt Romney and Democrats guarding against another lackluster showing from President Barack Obama.

With polls tight at the national and state levels, Democrats are attempting to improve both the president’s performance and their post-debate spin in the hope of regaining the upper hand. But for downballot Republicans, the focus will be on Romney and whether his showing at Hofstra University in Hempstead, N.Y., will boost them as it did two weeks ago. 

“Up and down the ballot, Republicans are seeing improved numbers both within the base and swing vote,” said a GOP strategist who views reams of polling data at the district, state and national levels. “But the Republican ticket needs Gov. Romney to keep this momentum going into the closing weeks, and this debate is a critical opportunity to keep the field tilted in his favor.”

For Democrats, it’s not just about making sure Obama brings more energy and focus to his debate performance. 

According to Capitol Hill sources, the Obama campaign realized after the first debate in Denver on Oct. 3 that it wasn’t just the president’s poor performance that led to an overwhelming perception that Romney won the debate. In the post-event spin room, where Republicans and Democrats attempt to declare their candidate as the victor in the moments after the debate, GOP surrogates far outnumbered and outperformed Democratic ones — a scenario that left the campaign scrambling.

At that first debate, Obama’s campaign had largely limited its response team to top campaign advisers, while Republicans deployed a more diverse lineup of seasoned lawmakers and rising political stars. The result was that more important people, often elected officials with broad appeal in states across the country, were articulating Romney’s message while advisers from Chicago were trying to counter the GOP narrative.

Republican Sens. Rob Portman (Ohio), John Thune (S.D.), Kelly Ayotte (N.H.), Marco Rubio (Fla.) and Orrin Hatch (Utah) were among the GOP Hill power players in the spin room who got ample air time. Their Democratic counterparts were nearly impossible to find. But for the Long Island town meeting debate tonight, Team Obama has lined up a who’s who of Democratic lawmakers to join the post-debate messaging war. 

In addition to the usual Obama campaign advisers — David Axelrod, Stephanie Cutter, Jim Messina and Robert Gibbs — the spin room will have appearances from Democratic Sens. Dick Durbin (Ill.), Charles Schumer (N.Y.) and John Kerry (Mass.), Democratic National Committee Chairwoman Rep. Debbie Wasserman Schultz (Fla.), as well as Reps. Xavier Becerra (Calif.), Chris Van Hollen (Md.), Nydia Velázquez (N.Y.) and Karen Bass (Calif.). The campaign is also bringing in Democratic Govs. Martin O’Malley (Md.) and Deval Patrick (Mass.) and former Govs. Jennifer Granholm (Mich.) and Ted Strickland (Ohio), among others. O’Malley was a designated surrogate for the first debate as well.

Deploying such a large group marks a significant shift in approach for the Obama campaign, which has been prone to go it alone during this year’s long campaign. The administration’s relationship with Hill Democrats has been icy at times, which led to opinions in the Capitol that White House officials believed they knew better than their Hill counterparts or, worse, that they did not need them to maintain control of the White House.

The Romney surrogate team did its job in the first debate, and Congressional sources say that the Romney campaign’s inclusiveness has been by design.

“You have to have more surrogates out there when you’re going up against the president of the United States,” said a Republican aide close to a Member who served as a surrogate in one of the debates. “There’s a lot more buy-in [from the party at large] when you’ve got people like Portman and Rubio and Ayotte speaking for the campaign.

“Team Romney has built a campaign to try to bring everyone in, bring in every tool they have to unseat a Democratic incumbent in a tough race … and they have a good set of surrogates who can hit many points,” the aide continued.

NBC News on Monday promoted Portman, who has been preparing Romney for the debates, and Cutter, who has emerged as Obama’s top trail surrogate, as the lead representatives for its prime-time coverage.

With just three weeks until Election Day, the campaigns have become a battle of teams. Downticket races are dependent on the presidential performances, and key states such as Ohio, Florida and Virginia, home to some of Congress’ most vocal Members, could decide what is increasingly looking like a tossup presidential race.

Roll Call predicts that Republicans will maintain control of the House on Election Day. The battle for the Senate is too close to call, but Roll Call gives a slight advantage to the Democrats to hold their majority. The outcome of the presidential race could determine how comfortable the GOP’s House majority is next Congress, and could affect which party is running the Senate.

As Republican campaign strategists digested polling conducted after the first debate, they saw better numbers for some GOP House candidates, including in partisan states where the presidential race is all but decided. For Republicans monitoring Senate races, the picture also improved, although Democrats still hold advantages in key races or are threatening in traditionally GOP territory. The Democratic Senatorial Campaign Committee disputed Republican contentions that Romney’s strong performance in Denver has provided coattails to GOP Senate candidates.

“National Republicans cannot point to any evidence that says this is true and the experts all say that the opposite is taking place,” DSCC spokesman Matt Canter said. “While Romney may have narrowed the margin, beleaguered Republican Senate candidates have failed to pick up any ground at all. 

“National Republicans must find themselves in a very dark place if they honestly think Mitt Romney’s campaign is going to save the day for them.”