Democratic lawmakers running for re-election in competitive districts this fall could be defeated if Gov. Andrew Cuomo and the Democrat-run Legislature refuse to revise the controversial bail reform law that lets loose dangerous criminal defendants.

Says who? New York state Democratic Party chairman Jay Jacobs.

“It’s going to be a problem if there are no changes to the law. More Democratic seats will be put at risk — and it will be tough — if we don’t do something,” Jacobs told The Post.

The new law bars judges from imposing cash bail on those accused of most misdemeanors and non-violent felonies.

Jacobs lauded the foundation of the law that scrapped a discriminatory policy that detained poor defendants pending trial simply because they couldn’t afford cash bail while letting others accused of identical crimes free because they had access to cash.

But he said there are exceptional cases where judges should have the discretion to detain a defendant with a prior criminal record — or who has been deemed a threat to public safety.

Jacobs’ extraordinary appeal to the governor and legislative leaders from his own party comes amid public outcry over the release of dangerous defendants who were then re-arrested and charged with committing more crimes. The backlash has caused a rift between progressive lawmakers who back the law and moderate to conservative Democrats in swing districts seeking changes.

While serving as state chairman, Jacobs also retains the title of head of the Nassau County Democratic Party. He particularly wants to protect the new wave of Democrats elected in the suburbs and upstate in 2018 that delivered the party majority control of the state Senate.

Jacobs said Republicans are using bail reform as a cudgel against Democratic lawmakers on Long Island and elsewhere. While he complained that GOP rivals are exaggerating the problem, he said legitimate public concerns have been raised about the new law.

“I’m hearing from Democratic county chairmen upstate [complaining about bail reform],” he said.

“Republicans have seen this as a vulnerability. They’re trying to paint Democrats as soft on crime. We need to neutralize this unfair attack on Democrats,” he said.

A recent Siena College poll found that New Yorkers have turned against bail reform.

Now 49 percent of New York state voters say the new policy is “bad” for New York compared to 37 percent who say it’s “good.”

That’s a stark turnaround from last April, when 55 percent of residents backed the law while only 38 percent opposed it.

Jacobs is hopeful that the law will be fine-tuned.

“Everybody is looking for a sensible solution to the problem,” he said.

Cuomo and Senate Majority Leader Andrea Stewart-Cousins (D-Yonkers) said they are open to tweaks to the law.

But Assembly Speaker Carl Heastie (D-Bronx), who is getting flak in briefings from some rank-and-file Dems seeking changes, is digging in his heels.

“Right now, it seems when the sun doesn’t come up, everyone wants to blame the bail law,” Heastie said Monday of the law, which went into effect New Year’s Day.

“I want judges, DAs, the police departments, sheriffs to work with the Legislature to try to make the law work,” Heastie said. “I think a month and three days in, people have already painted positions of what they’d like to see changed.”

He also downplayed the briefings his staffers held with concerned Assembly Democrats about the new bail law, as reported by The Post last week. The bail law was tucked into last year’s massive state budget and approved without a public hearing.

“We did it for members around the state, just because we are concerned about some of the misinformation that’s out there,” Heastie said of the briefings.