WASHINGTON (AP) – Armed with charts, video presentations, hired consultants and military experts, New England lawmakers are gearing up to persuade an independent commission that the region’s Navy, Army and Air Force bases are worth keeping open.

The key forum will be a hearing Wednesday before four members of the Base Closure and Realignment Commission, which will spend the day in Boston to take testimony on an issue that could drastically change the landscape of the military presence in New England.

Lawmakers and defense analysts consider it a longshot at being able to reverse the recent proposed realignment, which could cost New England three bases and nearly half of the jobs to be lost through base closures nationwide. But at least one base could have a chance of being saved: the submarine base in Groton, Conn.

“It is a very critical moment. It is the day when you arrive in court and lay before the judge the elements and facts of the case,” said Robert Gilcash, military analyst with McKenna Long Aldridge in Washington. “Make no mistake, it’s showtime.”

The main argument, lawmakers say, will be their base’s military value – a key component considered by the Pentagon in deciding what bases should be on the list. Officials have questioned the Pentagon’s scoring, including what military assets were included and how much each was worth.

“We’re going to heavily focus on military value,” said Sen. Christopher Dodd, D-Conn. “Even if they reconstruct the submarine base brick by brick, they’re not going to be able to reconstruct a long list of other assets there that have to do with the unique technology at Electric Boat, the submarine school, the maintenance there. And once you tear down the place, you can’t rebuild it again.”

At Wednesday’s hearing, officials from Connecticut, New Hampshire and Maine will each get two hours to make a presentation to the commission, while Massachusetts will get one hour, and Rhode Island – which escaped nearly unscathed – will get 30 minutes.

Besides the Groton sub base, also on the chopping block are the Portsmouth Naval Shipyard in Kittery, Maine, and Otis Air National Guard Base on Cape Cod. They’re among 33 major bases nationwide targeted for shutdown by the Defense Department in this fifth and latest round of base closings.

It will be Connecticut’s second struggle to get the Groton base off a closure list. They were successful in 1993, and may be able to repeat that success this year considering the skepticism expressed by some BRAC members about the plan.

“I think the community has a very good chance of convincing the commission that a mistake was made,” said Loren Thompson, defense analyst with the Washington-base Lexington Institute. “I think that the plan the Navy has proposed for moving the functions of the submarine yard is not credible.”

Gilcash said commission staff are very concerned about the severity of the impact of the Groton closing, and are asking a lot of questions.

Thompson said much of the nation’s skills in undersea warfare are concentrated in the Groton area – including submarine builder Electric Boat and the submarine school.

“You only need a straight majority of the commission in order to take a base off the list,” said Thompson. “And this commission is composed of self-assured people who are real experts and don’t mind telling the Pentagon, Sorry, you’ve got this wrong.”‘

In contrast, he said, the Portsmouth base probably can’t be saved because the submarine repair work done there can be moved. He also said it will be difficult to change Pentagon recommendations on Air Guard bases such as Otis, because they are part of a national strategy that the BRAC may not be willing to challenge.

But recent comments from the Coast Guard and BRAC Chairman Anthony Principi suggest there is some hope for both.

In a letter to Defense Secretary Donald Rumsfeld last week, Principi asked for more information on why the Pentagon chose to close Portsmouth rather than the Pearl Harbor shipyard.

Sen. Olympia Snowe, R-Maine, took that as a positive sign, saying it will give a boost to the state’s arguments that Portsmouth is the most efficient shipyard, and shifting work to the other three yards will create backlogs and hurt Naval operations.

But she said it won’t be easy.

“It’s hard to get into their heads,” she said. “We just have to make sure that we’re giving them all the data, and where the Defense Department has deviated from the criteria, and hope the commission agrees.”

Meanwhile, Coast Guard officials last week challenged the Pentagon’s decision to close Otis Air Guard base, warning that moving the fighters and personnel will dramatically increase costs for the Coast Guard, which shares space at the Massachusetts Military Reservation on the Cape.

Sen. Edward M. Kennedy, D-Mass., said Otis – where the first fighters were launched in response to the Sept. 11 attacks – is critical to the defense of the entire region. Kennedy, who met with Coast Guard Commander Adm. Thomas H. Collins, said closing Otis would shift at least $17 million in annual costs to the Coast Guard, possibly forcing the guard to move – undercutting rescues and security in the area.

Members of Congress from New England have been meeting regularly to hone their presentations and pour over the documents for weaknesses in the Pentagon’s arguments.

“The stakes of failing are so high,” said Rep. Rob Simmons, R-Conn. “Not only for the communities, but for the nation and national security.”