National issues are being debated in New York’s special election Tuesday, but the outcome will be determined by purely local factors.

The race will come down to “who gets their vote out,” said John Jasper Nolan, Republican Party chairman in the 20th District’s most populous county, Saratoga. “That’s been the issue from day one.”

Nolan is focused on mobilizing party volunteers to turn out for GOP nominee Jim Tedisco, while the Democratic nominee, Scott Murphy, gets the aid of an AFL-CIO field operation.

Get-out-the-vote activity took on a heightened sense of urgency after a poll March 27 showed the race in a dead heat. Likely voters polled March 25 and 26 by Siena Research Institute gave Democratic candidate Scott Murphy a narrow 4 percent lead over Tedisco, with a margin of error of 3.2 percent.

Given the compressed schedule of the race and low turnout common to special elections, organizers on both sides say get-out-the-vote efforts will be the determining factor in the race.

The campaign has become part of a larger debate over President Obama’s handling of the economy, “But I still think the general special election patterns still apply,” said Danny Hayes, a Syracuse University political science professor who studies electoral behavior.

“We know that people are more likely to turn out when it’s easier getting information about elections,” Hayes said. “You go down to a situation like this where you have a single race on the ballot at an unusual time” and “people are less tuned in.”

For the partisan forces on the ground, motivating their bases — the people who stay engaged between presidential elections — is critical. It’s also somewhat unpredictable.

Republicans in the upstate district had a 70,600 voter-registration edge as of November 2008. But the district voters sent moderate Democrat Kirsten Gillibrand to Congress twice, in 2006 and 2008, and gave Obama a narrow edge over his Republican opponent, Sen. John McCain , in the November presidential election.

“We know we have a larger majority of Republicans, it’s us getting them out to vote,” said Nolan, who has served as Saratoga’s Republican party chair for the past 22 years. “If we sit back, we could lose it.”

Tedisco, moreover, has been having problems consolidating GOP support.

The March 27 Siena poll showed that 64 percent of Republican respondents said they would vote for Tedisco, but 27 percent said they were voting for Murphy. Murphy was favored by 84 percent of those who identified themselves to the pollsters as Democrats.

To overcome that, the Tedisco campaign bragged about putting hundreds of volunteers in the field over the weekend.