On the night of the Democratic primary election, which he won over former Conn. Secretary of State Susan Bysiewicz ’83, U.S. House Rep. Chris Murphy watched results come in at the Omni Hotel in New Haven — rather than in his home district.

The latest polls show Murphy with a small lead over Republican Linda McMahon in the race to replace U.S. Sen. Joe Lieberman ’64 LAW ’67. New Haven, which has the largest number of registered Democrats in the state, is uniquely positioned to deliver Murphy a victory depending on how many city Democrats turn out to the polls.

Murphy, who currently represents the Connecticut’s fifth congressional district in the U.S. House of Representatives, has run much of his campaign out of his New Haven headquarters on Whalley Ave. with the help of a large grassroots campaign of volunteers.

“New Haven is going to play a critical role in what is sure to be a close election,” said Eli Zupnick, a spokesman for the Murphy campaign. “We think that the more voters learn about the differences between Chris Murphy and Linda McMahon, the stronger Chris’s showing will be on election day.”

Multiple spokespeople for the McMahon campaign did not respond to requests for comment.

There are over 45,000 registered Democrats in New Haven out of 60,000 total registered voters, according to a spokesman for the New Haven Registrar of Voters. In contrast, there are only 2,400 registered Republicans in the Elm City.

In 2010, New Haven Democrats are widely believed to have pushed Gov. Dannel Malloy to victory, according to Paul Bass ’83, editor of the New Haven Independent. Bass said that though Malloy beat Republican opponent Tom Foley by over 5,000 votes, Malloy would have lost by 13,000 without New Haven’s support.

Ward 3 Alderman Jacqueline James, president of the New Haven Democratic Town Committee, said the party sets up a voter turnout strategy each election cycle involving phone calls, door knocking and driving voters to the polls on Election Day. She said that her party is working to increase Democratic voter turnout this year, aiming to ensure 45,000 New Haven voters head to the ballot box this November compared to the 35,000 who did so in 2008.

James added that though she has heard reports of McMahon hiring representatives in the local black community, she does not believe the McMahon campaign has laid a grassroots campaign in New Haven. McMahon’s campaign headquarters are located in North Haven, although she has spent significantly less time than Murphy in the Elm City.

“It would really be a waste of her time,” James said. “We are a staunch Democrat town. We have some Republicans, but not many.”

A spokesman for the Republican Party of Connecticut declined to comment on the nature of Republican voter turnout strategies across the state.

Wayne Winsley, a Republican who is challenging incumbent Democrat Congresswoman Rosa Delauro to represent New Haven in the U.S. House of Representatives, said he disagrees with the notion that New Haven is unwinnable for Republicans. He said that his strategy of walking city streets and greeting voters is bringing him recognition that few other Republicans have garnered in the city, and he hopes that this recognition will deliver him a win in November.

“Conventional wisdom says that [DeLauro’s congressional district] is unwinnable except for a Democrat,” he said. “What I am telling you is, every once in a while, something comes along that defies conventional wisdom. My campaign is that thing.”

DeLauro has raised $872,406 so far this election.