Baker promised not to raise taxes. Facing a challenger, he rarely has to defend that promise

Fighting a mountain-size deficit in the public polls, Jay Gonzalez has whacked Governor Charlie Baker on the MBTA. He’s attacked the Republican on gas pipelines and the State Police. He’s tried to corner Baker on his support for a conservative Senate candidate.

But what about Baker’s central 2014 campaign promise to voters that he wouldn’t raise taxes? As a debate moderator pressed the governor on the issue last week, Gonzalez, the Democratic challenger, watched, waited his turn, and then . . . changed the subject.

“But we’ve got to make sure that people understand the choice here on transportation,” Gonzalez stressed.

For a governor who ran on not raising taxes and fees, Baker has rarely had to defend it against Gonzalez, a progressive Democrat who has built his campaign on promising to pursue tax hikes on the wealthy and invest, he says, in ways Baker is unwilling.

On Tuesday, Gonzalez charged in a statement that Baker has “waffled on taxes.” But his own tax-heavy platform has otherwise left the former state budget chief unable — if not unwilling — to scrutinize Baker on whether he honored his pledge, even after Baker signed into a law a $800 million payroll tax and a $2 surcharge on car rental transactions, among other new revenue generators.

Jay Gonzalez, meet box.

“To start with, it’s hard for a Democrat to criticize someone for raising taxes they think are necessary. Here, he’s already made a point to basically say this guy should be taxing more,” Ray La Raja, a political scientist at the University of Massachusetts Amherst, said of Gonzalez. “That’s a tough one.”

With less than two weeks until the Nov. 6 election, Gonzalez is trying to scratch out as much ground as possible against an incumbent who’s led by nearly 30 points in recent polling. And he’s done so by heavily promoting his own tax plans while criticizing Baker for not presenting his own.

Baker’s own nuanced dance with new taxes has weaved through his first term, during which he has defended his support for new revenue when he says it supports new programs or levels a “playing field,” as in the case of new taxes he backs on short-term rentals, such as Airbnb’s. The Republican has reiterated his opposition to broad-based increases on the income or sales tax, repeatedly filing budgets without them. And he’ll continue to oppose them if reelected, said campaign spokesman Terry MacCormack.

“As a general rule, I don’t think balancing the budget should be coming out of the pockets of the taxpayers,” Baker told reporters following a WBZ-hosted debate this month. “That should be left up to us. That’s our job.”

The debate about how closely he’s hewed to that pledge reared its head last week, when Jim Braude posed a not-so-hypothetical situation to Baker about a governor who imposed a quarter-billion-dollar assessment on some employers and new taxes to backstop a paid medical and family leave.

“Would you say that person is a no-new-taxes governor?” Braude asked during Baker and Gonzalez’s second debate, at the WGBH-TV studios in Brighton.

In response, the Republican defended the payroll tax, noting it was tied to the so-called grand bargain between activists, business leaders, and legislators to keep several ballot questions from going to voters in a “deal that people can live with,” Baker said.

“It’s an $800 million increase to support that new benefit, yeah,” Baker said, adding that he didn’t raise taxes as he closed what he called a $1 billion structural budget deficit after taking office.

Largely absent from the back-and-forth was Gonzalez, who in the debate — and elsewhere — has highlighted his plans to tax the endowments of the state’s wealthiest colleges to generate $1 billion in new taxes.

He also said he’d push a constitutional amendment through the Legislature to raise the state income tax on those making $1 million or more, after the Supreme Judicial Court rejected a ballot question that sought to do the same. Gonzalez has acknowledged that passing such a measure would take an entire four-year term under constitutional requirements.

Baker has criticized the plans, questioning whether they’d even pay for all of Gonzalez’s promises on transportation or moving toward a single-payer health care system.

Asked last week if Baker broke his campaign pledge, Gonzalez said: “I don’t know.”

“I’m concerned about the next four years, and the next four years he’s not proposing to do anything in this regard,” Gonzalez said. “I know it’s not easy for a political candidate to say, ‘I’m going to raise taxes.’ But we can’t afford not to.”

In a statement Tuesday, Gonzalez sharpened his rhetoric somewhat, arguing that Baker “has waffled on taxes,” among other topics, including his support for US Senate candidate Geoff Diehl. Baker said during the WGBH debate that he hadn’t decided whether he’d back the conservative Republican, but told reporters afterward that he would.

“What does Governor Baker actually stand for?” Gonzalez said in his statement. “He is constantly trying to have it both ways and basing important decisions on political calculations.”

There’s also the calculation of whether such a tactic would even catch voters’ attention. Lou DiNatale, a veteran Democratic operative, said jumping into the fray about Baker’s record on taxes probably offers the Democrat few victories.

“It’s too much of a reach, in this environment,” he said, arguing races in this election cycle are dominated not by policy but by personality.

There’s another challenge, too: It’s awkward for Gonzalez to attack Baker on his tax pledge, given his own push for more of them, said Jeffrey M. Berry, a political science professor at Tufts University.

“Judging the governor against all his promises is a good talking point,” Berry said.

“But I think what Gonzalez needs to do is grab the imagination of Massachusetts voters and make them understand that the Gonzalez administration is somehow going to make their lives better.

“He’s tried to do that and so far has failed,” he added, “because I don’t think many people have paid attention to him.”