On Tuesday, it was all about taxes.
Standing in a cinderblock auto body shop in Mattapan, Republican Senate candidate Gabriel E. Gomez blasted his Democratic opponent, US Representative Edward J. Markey, for voting to raise taxes 271 times during his 36 years in Congress.
“He’s raised taxes on everything from gas to a pint of Sam Adams beer,” said Gomez.
The tax attack was the latest salvo from a candidate who has bounced from criticism to criticism as he takes on Markey in the race for the Senate seat long held by John F. Kerry.
In recent days, Gomez has accused Markey of being soft on national security, of resorting to “dirty” campaign tactics, of “hiding” from voters on the campaign trail, and of being the “poster boy” for term limits.
While some say the rotating messages are a sign of a campaign methodically rolling out attacks, others say Gomez is searching for a message that will resonate with voters before the June 25 election.
“It’s a campaign without a theme, and they’re diluting their messaging to the point where, once this campaign concludes, it’s going to be: ‘So what was his pitch again?’ ” said former state treasurer Joseph D. Malone, a Republican who lost in his bid to unseat Senator Edward Kennedy in 1988. Malone endorsed Michael J. Sullivan in the GOP primary, but has not backed Gomez in the general election.
Shifting from attack to attack can sometimes be a sign that a candidate is firing off every bit of negative information gathered by consultants, instead of driving a consistent line of argument. But Lenny Alcivar, a Gomez spokesman, defended the candidate’s shifting targets, saying there is a unifying theme: Each criticism contrasts Markey’s career in Washington with Gomez’s background as a Navy SEAL turned private equity investor.
“We view this as a systematic example of the fact that, on issue after issue, Congressman Markey has a 37-year record in Washington that is weak, ineffective, partisan, and the epitome of the old way of thinking,” Alcivar said.
In its response to Gomez Tuesday, the Markey campaign did not challenge the figure of 271 votes in favor of tax hikes and instead focused on the Malden Democrat’s support for measures to lower taxes.
Markey “has voted to enact more than a trillion dollars in tax cuts for small businesses, working families, and the middle class,” said Andrew Zucker, a campaign spokesman.
A GOP official in Washington said he expected Gomez to continue to focus this week on Markey’s record on taxes.
The official said Gomez’s focus on national security last week was prompted by Senator John McCain’s visit and Memorial Day. At the same time, it was also designed to help Gomez redirect the debate away from a $281,500 tax deduction he took on his Cohasset home in 2005.
Markey, meanwhile, has focused more narrowly on the candidates’ differences on gun control and abortion rights.
On Tuesday, after Gomez launched his tax criticism, Markey publicized a commercial he had quietly launched Friday that highlights his support for higher taxes on the wealthy and for closing corporate tax loopholes. Markey’s decision to wait until after Gomez’s attack to promote his tax stance underscored for some his less aggressive approach to the campaign.
“He’s simply trying to lie low and ride the tremendous Democrat voter registration advantage in Massachusetts,” said Ryan Williams, a Republican strategist. “He’s not really presenting a compelling argument for a promotion. He’s just trying to be a Democrat and win because Democrats have a statewide advantage in Massachusetts, and that’s insulting to voters.”
Gomez unveiled his tax attack at Auto Service and Tire, a family-owned shop on Blue Hill Avenue that Scott Brown visited during his Senate race against Elizabeth Warren. After labeling Markey a serial tax raiser, Gomez said he would lower the nation’s 35 percent corporate tax rate to below 30 percent and would close corporate tax and personal tax loopholes.
Asked which loopholes he would eliminate, Gomez cited two examples frequently targeted by Washington Democrats: tax breaks for corporate jet owners and a special “carried interest” tax break that benefits wealthy hedge fund managers and private equity investors such as Gomez.
“My solution is you’ve got to be bipartisan about this and address both sides,” said Gomez, who has declined to sign the no-new-taxes pledge that has been signed 219 members of the US House and was signed by Brown. “Everything should be open for discussion,” he said.
Joshua Miller of the Globe staff contributed. Michael Levenson can be reached at mlevenson@