Hartford - Southeastern Connecticut and its submarines emerged Wednesday as hot topics in the newly defined Senate race between Democratic Congressman Chris Murphy and Republican Linda McMahon.

The day after the primaries narrowed the candidate field from four to two, the campaigns challenged each other to a future debate in Groton, home to Electric Boat and the Naval Submarine Base.

The Murphy camp believes it can capitalize on remarks McMahon made outside the EB gates in June, when she demonstrated incomplete knowledge of the federal Base Realignment and Closure process, known as BRAC.

But the McMahon campaign thinks Murphy committed a graver offense this year when he twice voted against major defense spending bills containing funding for two-per-year sub production at EB.

Murphy, who represents the 5th Congressional District, was the sole member of Connecticut's five-person House delegation to vote last month against a $604 billion 2013 defense appropriations bill that included $4.8 billion to continue producing the Virginia-class attack submarines in Groton and prevent what could be a one-year drop in production from two boats to one in 2014.

The bill contained additional money to continue development of an Ohio-class replacement submarine program that is currently under way inside the former Pfizer building in New London.

Both defense bills nevertheless passed the House and are awaiting action in the Senate.

Murphy voted against the bills because they contained "open-ended funding" for military activities in Afghanistan, his campaign spokesman, Ben Marter, said Wednesday.

"Chris believes we should end that war as quickly as is safely possible. Right now, the war in Afghanistan is costing $2.2 billion every week."

By comparison, each new submarine costs roughly $2.6 billion.

But a spokesman for the McMahon campaign, Tim Murtaugh, said it was wrong of Murphy to greet workers at the EB gates last week and pledge to protect submarine work after having opposed the bills.

"It takes some serious gall to go down there and shake hands with the EB workers, knowing that you voted against the funding that keeps their jobs," Murtaugh said.

During the EB trip, Murphy was joined by U.S. Rep. Joe Courtney, D-2nd District, who successfully obtained funding for building two submarines per year.

Courtney has endorsed Murphy for the Senate and also opposes an "open-ended commitment" to Afghanistan. Yet he voted for both defense bills and issued news releases at the time cheering their passage: "The Second Congressional District is home to tens of thousands of defense-related jobs, and during these tough economic times I am pleased to have secured funding that will protect these jobs and grow our economy."

On Wednesday, he stood by his support for Murphy.

"Many Americans appreciate Congressman Murphy's calls for a quicker drawdown of American forces in Afghanistan," Courtney's campaign manager, Emma Pietrantonio, said in a statement. "Congressman Courtney has no doubt that, as a senator, Murphy will be a strong advocate for SUBASE New London, Electric Boat and increased submarine production."

She also credited Murphy's "far superior" knowledge of the BRAC process and commitment to avoiding future rounds of it.

McMahon committed her Groton gaffe by telling a reporter that, if elected to the Senate, her vote for or against another BRAC round would depend on the proposed cuts.

The problem with the remark is that under the BRAC process, lawmakers authorize a round of base closings before they know what bases will later appear on the list, which is drawn up by an independent commission.

BRAC was created in the late 1980s to minimize the role of politicians in closure decisions. The Groton base barely escaped closure when it was targeted in 2005.

McMahon has since vowed to "fight tooth and nail" to keep the base open and protect EB jobs.

Murphy has promised that he is deeply committed to the submarine base and EB. "He's voted for millions of dollars in improvements to help keep it off the closure list in the future," said Marter, his campaign spokesman.

"We look forward to debating in Groton, where McMahon will have to face the people in southeast Connecticut that she'll put out of work with her on-again, off-again support for closing the sub base," Marter said.

Neither candidate has proposed a specific date or location for a Groton debate. The McMahon campaign announced Wednesday that it is open to participating in four live televised debates before the Nov. 6 election, but refused Murphy's invitation for a jobs-focused debate as early as Tuesday, dismissing the idea as a "campaign stunt" because it would take more time to organize a venue, sponsor and television coverage.

"Historically, debates in high profile races like this happen in the fall, when people are paying attention," Murtaugh said.

Murphy participated in three one-on-one debates between the spring conventions and Tuesday's primary with his Democratic opponent, Susan Bysiewicz. McMahon joined in two with her defeated challenger, Republican Christopher Shays.

j.reindl@theday.com