If H. Richter Elser ’81, the Republican challenger in Tuesday’s mayoral race, thinks he has a chance of unseating incumbent Democrat John DeStefano Jr, he may be living in the pre-Cold War era. The last Republican mayor to ascend to the office, after all, did so when Harry Truman was still president.

But Elser is betting that when voters go to the polls, they will think as he does: that past accomplishments are not a sure indication of future successes. Still, Elser, whose moderate political profile and willingness to work within the existing political framework could make him palatable to New Haven’s overwhelmingly Democratic electorate, faces long odds against a mayor who has won acclaim even from sometime critics during his 14 years in office.

Elser was a presence in downtown New Haven long before he decided to run for office. Two years after graduating from Yale, Elser opened his own bar, Richter’s, on the site of the former Taft Hotel, which by that time had been turned into apartments. Only a short walk from Old Campus, the bar is known among New Haven residents for its tall glasses of beer, which patrons order by the yard.

For over two decades, the bar and its owner have witnessed the struggles and successes of downtown: the crime and empty storefronts that plagued the area in the late 1980s and early ’90s, but also its revitalization — which Elser credits in large part to DeStefano.

In a city highly supportive of the Democratic Party — the party holds 29 of 30 seats on the Board of Aldermen — running as a Republican might seem like enough of a disadvantage for Elser. But praising the man he hopes to defeat?

That is the reality of running against an incumbent who has presided over more than a decade of what even critics concede is improvement and growth in the city.

“Since 1993, John DeStefano has done great stuff for New Haven,” Elser said. “But today, New Haven is less able to live within its means. Its actual tax income contributes less than it ever has to total budget.”

Elser’s campaign focuses not on the accomplishments of the past but on what he sees as the necessary steps forward for a city that is courting disaster by always expecting that someone else — Yale, Connecticut, the federal government — will foot the bill.

In mayoral debates throughout the campaign, Elser has stressed that he does not oppose many of the programs supported by the mayor, such as youth after-school programs. But he has said he thinks private organizations and community groups — secular and religious alike — would provide a better avenue for pursuing the city’s goals.

But Elser has objected vocally and repeatedly to the Elm City ID program, which provides legal identification and city services to New Haven residents regardless of their immigration status. He likens the program to the urban renewal programs of New Haven’s mid-century, eight-term mayor.

“Mayor [Richard] Lee lured 100,000 people up from the South,” Elser said. “Today, you still see North Carolina license plates around the city.”

To Elser, the license plates are a sign of broken promises — of the factories that offered the hope of jobs but later closed, leaving thousands out of work. He said the city should not make the same mistake today by offering promises to illegal immigrants that, as a city, it cannot keep. Instead, he said, New Haven should be helping them on the path to citizenship.

But Elser said he ultimately objects to the municipal ID program because it is “a distraction to the city,” a contention the mayor and his administration hotly contest.

Kica Matos, the city’s community services administrator and the creator of the ID program, said New Haven — 10 percent of the population of which is made up of undocumented immigrants — was forced to act in the absence of federal legislation to deal with the challenges of a growing immigrant population. Immigrants were increasingly becoming targets for “unscrupulous employers and criminals,” she said.

His position on the Elm City ID card notwithstanding, Elser’s policies on many issues are not necessarily what political conventional wisdom would expect.

At a mayoral debate last week, Elser’s fellow challenger — Green Party candidate Ralph Ferrucci — criticized DeStefano’s administration for allowing neighboring towns to drop homeless residents in New Haven, which provides them access to shelters. But Elser said New Haven should be willing to take on the responsibility.

“New Haven can deliver services better than the other towns can,” Elser said. “To deliver them effectively requires [population] density. But New Haven needs to reach out and convince the other towns to help subsidize the costs, and then they can drop off people legally.”

Still, Elser disagrees with the mayor on numerous issues of policy.

He said he thinks DeStefano is not doing enough to incorporate the charter system begun at New Haven’s Amistad Academy middle school into the local public school system. And Elser said students at Gateway Community College, which has a number of classes that cover topics in various medical fields, would be better served if their campus were located near the highway — which is by the medical school and the biomedical businesses — rather than downtown.

But despite his disagreements with DeStefano, he said he realizes that to accomplish anything in such a Democratic city, he would have to work within the system that is already in place.

First, though, Elser will have to make a case that a city of predominantly Democrats should consider voting for a Republican.

Aldermen interviewed said that while within individual wards voters can relate to candidates as community members rather than as members of political parties, such a dynamic becomes decidedly more difficult on the city level.

“There is large population that will simply not entertain the idea of voting for a Republican,” Ward 13 Alderman Alex Rhodeen said. “No matter how competent, with that ‘R by their name, they are definitely fighting an uphill battle.”

Elser said he has no interest in simply becoming a perennial candidate. If he does not receive a substantial enough percentage of the vote, he said he would not run in future elections.

“I’m not a masochist,” he said.

But his campaign strategy seems focused more on turning out his base than winning over Democrats.

“Give me a time and place, and I’ll come speak,” he said. “I often go out to the house of someone who has invited friends and neighbors.”

He said he spoke last week with the Yale College Republicans, some of whom will likely help put up campaign signs in before Tuesday’s election.

Given the low turnout in New Haven municipal elections, he said he only needs a few thousand votes from undecided voters in addition to reliable, solidly Republican votes. Both parties are losing their relevance, he said, pointing out that 48 percent of New Haven residents are not registered with a party.

“The Democratic party isn’t as unified as it seems,” he said. “It’s split between black, Hispanic and Italian caucuses.”

The polls will be open from 6 a.m. to 8 p.m. on Tuesday.