NEWARK, N.J. — Democrats running in the primary for New Jersey governor on Thursday attacked front-runner Phil Murphy, saying he is using his wealth to buy political support and questioning his progressive stances.

But Murphy deflected the criticism raised at the second and likely final candidate’s debate held on NJTV. He said he has worked hard to win endorsements and that he holds his political positions earnestly.

The four leading Democrats in the June 6 primary mostly agreed on the issues facing New Jersey, such as possibly raising taxes on millionaires, meeting public pension obligations and hiking the minimum wage to $15 an hour. But Jim Johnson, state Sen. Ray Lesniak and Assemblyman John Wisniewski pounced at the chance to knock down Murphy over the personal cash he’s poured into the campaign and his time as an executive at Goldman Sachs.

“We have a candidate who has made the system awash in money. It’s obscene the amount of money,” Wisniewski said. “It’s pay-to-play at its worst.”

Murphy, who has put $15 million of his own money into the race so far, denied he bought the backing of New Jersey’s 21 influential Democratic county party chairmen, who exercise discretion over ballot positioning.

“I haven’t bought any county chairs with all due respect,” Murphy said. “We’ve worked very hard to earn those endorsements.”

Wisniewski also said that Murphy had backed fracking during a speech in Germany, where he served as ambassador for former President Barack Obama, but Murphy denied it. He said he was discussing fracking in the context of geopolitics and Russia. Murphy also came under attack for investing in corporations opposed by environmental groups that have backed Murphy. Murphy promised to put his holdings into a blind trust if elected.

Johnson seized on the point, though, telling Murphy that his current progressive stances were contradicted by his investments and previous comments.

“What is it in your time at Goldman Sachs that should give anyone any assurance that the progressive values you’re talking about today are progressive values you’ve acted on at Goldman Sachs,” Johnson asked.

Murphy said he didn’t need a lecture on liberalism.

“Progressive values are not a book that I have to read or an abstract concept. I’ve lived it my entire life,” Murphy said.

Recent polls show Murphy is the front-runner, though most voters haven’t made up their mind about who they’ll back, the surveys show.

Johnson is an attorney and former Clinton administration Treasury official; Lesniak has served as a state senator for three decades; and Wisniewski co-chaired the panel investigating the so-called Bridgegate scandal involving traffic lanes being closed on the George Washington Bridge near Fort Lee by members of Republican Gov. Chris Christie’s administration.

The four candidates are vying to succeed Christie, who is term-limited, in one of only two of the country’s statewide races this year, along with Virginia.

The Democrats held their first debate on Tuesday. The debate lacked the kind of rhetorical fireworks that accompanied last year’s presidential debates, but offered candidates a chance to present themselves to voters.

Republicans will meet May 18, also in Newark on NJTV.