Sen. John Kerry’s campaign advisers told Democratic Senators on Tuesday that a lack of money prevented the Massachusetts Democrat from adequately defending himself when he first clinched his party’s presidential nomination, but they vowed not to allow GOP criticisms to go unanswered in the future.

Once it became clear in early March that Kerry would be the Democratic nominee, President Bush’s re-election campaign launched a barrage of negative advertisements questioning the Senator’s national defense credentials and accusing him of being a proponent of higher taxes. Having just emerged from a bruising primary battle, Kerry was financially strapped and it took the newly minted nominee several weeks to build up a sufficient war chest to not only post an effective defense but also to launch a strong offense against Bush.

Democratic Senators, who privately had wondered why Kerry appeared to stand idly by while Bush spent millions of dollars attacking him, embraced the campaign officials’ explanation and pledged to help echo the Senator’s political platform in the coming months.

“They addressed the issue that many people have raised and that is: ‘Why did John Kerry let George W. Bush beat up on him?’” said Sen. Dick Durbin (D-Ill.). “The simple, honest answer is Kerry was almost broke, but since then he has had dramatic success raising money.

Meanwhile, on the other side of the Capitol, several key Kerry aides met privately with House Minority Leader Nancy Pelosi (D-Calif.) on the state of the campaign. Pelosi has been privately pushing Kerry to name his vice presidential pick soon, to give the Senator a surrogate to defend the GOP charges.

Vice President Cheney has helped lead the Bush administration offensive against Kerry, and Pelosi wants to counter that effort, House Democratic leadership sources said.

The Massachusetts Democrat dispatched former New Hampshire Gov. Jeanne Shaheen (D) to Capitol Hill on Tuesday, along with several other top aides, to brief his Senate and House colleagues. Shaheen, who serves as national chairwoman of Kerry’s campaign, met privately with Senators on Tuesday and meets with the House Democratic Caucus this morning.

“So we are now in a position where we can be competitive,” said Durbin, whom Kerry recently appointed co-chairman of the Democratic National Committee.

Unlike the 2000 Democratic presidential nominee, then-Vice President Al Gore, Kerry has made it a top priority to keep his Democratic colleagues abreast of his campaign strategy.

“She wants to talk to Members about what the campaign is doing and how we can work together,” said a House Democratic leadership aide. “This is part of their effort to reach out and talk about the campaign.”

House Members are heading to the floor to coordinate their one-minute speeches with the Kerry message, and will revise their floor activity to refute “any attacks by the GOP about Kerry,” said the leadership aide.

“When we see a coordinated attack from the Republicans, we have to be prepared to fight back and we are,” said the staffer. “It will manifest itself in positive statements about Senator Kerry and we will be prepared to respond to the attacks from the other side.”

The Kerry officials are laying out poll numbers from the 17 battleground states that are expected to determine the winner of this year’s presidential election and are previewing television advertisements the campaign is set to air.

“I though it was excellent,” Sen. Evan Bayh (D-Ind.) said of the campaign officials’ presentation to the Senate. “Their research verified most of our intuition that his biography is a very strong asset for John. When more people find out about some aspects of his background, the more they like him.”

In recent days, Kerry’s past, specifically his service in the Vietnam War and his subsequent opposition to it, has been the subject of political sniping between principles of the two campaigns. Top Republicans including close Bush adviser Karen Hughes and Cheney have publicly questioned Kerry’s story about how he discarded his service medals during a 1971 protest against the conflict. In turn, Kerry charged Bush might have sidestepped his National Guard duty during the Vietnam War.

Bayh said Kerry’s appeal extends beyond his service in war, but he acknowledged the Massachusetts Senator’s two tours of duty in Vietnam — where he was awarded three Purple Hearts, a Silver Star and a Bronze Star — is a compelling story to voters.

“The fact is he risked his life to save other people in combat,” Bayh said.

In an interview prior to the meeting, Shaheen said this was just one of many briefings that campaign officials will deliver to Congressional Democrats as the race unfolds in the coming months.

“This is really one of those [meetings about] this is where we are and this is where we are going,” said Shaheen.

So far, Shaheen said the Kerry campaign “feels very good” about how Congressional Democrats have responded to his candidacy.

“They have stepped in and carried the message and been very vocal throughout since John Kerry clinched the nomination,” she said. “They recognize we are in this together and everybody’s goal is to get rid of the current president.”

Shaheen is expected to deliver a similar briefing today to House Democrats. Sen. Kent Conrad noted that this is the point in a campaign when a candidate “goes through a testing phase” as he shapes his message and, so far, the North Dakota Democrat thinks Kerry is doing “pretty well.”

“This is the beginning of his defining the issues and I think he is off to a pretty good start,” Conrad said.