Candidates for the U.S. Senate seat being vacated by Sen. Joseph Lieberman ’64 LAW ’67 are gearing up for this May’s nominating conventions.

Senate hopefuls have campaigned and participated in debates in advance of Democratic and Republican primary conventions held on May 12 and May 18, respectively, where delegates at each convention will endorse one nominee and allow any candidate with at least 15 percent of delegates’ votes to be put on the ballot. U.S. Rep. Chris Murphy is the frontrunner for the Democratic nomination, while former wrestling executive Linda McMahon will be endorsed by the Republican Party.

A Quinnipiac University poll released on March 22 — the most recent numbers available on the Senate race — shows McMahon, who ran against Sen. Richard Blumenthal LAW ’73 in 2010, ahead of former U.S. Rep. Chris Shays by nine percentage points. Murphy, meanwhile, leads the Democratic pack with 37 percent, ahead of former Connecticut Secretary of State Susan Bysiewicz ’83 by 12 points and State Rep. William Tong by 33 points.

According to the poll, McMahon would lose the seat to Murphy 52 percent to 37 percent and to Bysiewicz 49 percent to 39 percent, while beating Tong 49 percent to 39 percent, should she win the nomination. Shays, however, would run neck and neck with both Murphy and Bysiewicz, trailing Murphy by one percentage point and leading Bysiewicz by the same margin.

Douglas Schwartz, the Quinnipiac University poll director, attributes the uncertainty reflected in the poll numbers to the crowded fields in both parties. Currently, five candidates are running in each party’s primary race.

“It muddles things because the voters are seeing five candidates when there are really only two or three on each side,” Schwartz said. “My sense is that it will settle down in May.”

As a result, Schwartz added, debates have attracted little attention from the media and general public. During the debates, Shays spoke of his electability and McMahon touted her business experience as the former CEO of World Wrestling Entertainment, according to the Connecticut Mirror.

So far, McMahon and Murphy have raised the most cash in their fields. According to campaign finance figures released on April 13, Murphy’s campaign has over $3 million on hand, while McMahon’s has just under $2 million. Bysiewicz has $1 million, and Tong’s campaign reported slightly above $200,000.

Schwartz said that commentators expect McMahon, who spent $50 million of her own money on her 2010 Senate bid, will contribute private funds to this year’s campaign. So far, McMahon has already loaned over $1 million and donated over $600,000 to her campaign. Schwartz emphasized that McMahon faces a tough primary race even with her financial advantage.

Despite trailing Murphy in both fundraising and popularity, spokesmen for the Bysiewicz and Tong campaigns both expressed optimism about their candidates’ futures.

Jonathan Ducote, Bysiewicz’s campaign manager, said Bysiewicz is the only candidate on either side to represent the middle class, as she is the only candidate with a plan to regulate Wall Street once she arrives at the Senate.

Marc Bradley, campaign manager for the Tong campaign, highlighted Tong’s personal story as an immigrant, noting that he managed to widen his support base from Stamford, Conn. — which he representes in the state House of Representatives — to the entire state.

“I think [Tong] has built a strong base of support, and we look forward to having that conversation in the summer and onto the fall,” Bradley said.

A Republican has not been elected to the Senate from Connecticut since 1982.