WASHINGTON — Former President Bill Clinton tried to tamp down criticism for his confrontation with black protesters at a rally to support Hillary Clinton’s White House bid — an incident that experts say demonstrated a major vulnerability of the usually adroit campaigner.

“He’s certainly a master politician, but he has a history of letting his temper sometimes get the better of him,” said Democratic strategist Garry South, who worked on the presidential campaign teams of Jimmy Carter and Al Gore.

The former president drew fire for clashing with Black Lives Matter activists last week over the 1994 crime bill he signed, which imposed steep drug crime penalties and sentences and expanded the prison system.

Hillary Clinton’s support for the bill as first lady — she said it would bring “the kinds of kids that are called ‘super-predators’ … to heel” — has been blasted by critics who say the law helped fuel disproportionate over-incarceration of black low-level offenders. Both Clintons have since expressed dismay over some of the law’s effects and advocated for criminal-justice reform.

But last week Bill Clinton shouted down protesters, charging them with “defending the people who kill the lives you say matter,” and citing black lawmakers’ support for the law.

Clinton later expressed some regret, saying the remarks made him “almost want to apologize.”

Civil rights activist and author Michelle Alexander said Clinton’s remarks reinforced a false premise that black community members and lawmakers were “asking for ‘get tough’ measures and nothing else back in the 1990s” to respond to the country’s drug and crime epidemic.

“It is a gross distortion to suggest that black people wanted billions of dollars slashed from child welfare, housing and other public benefits in order to fund an unprecedented prison building boom,” Alexander said.

Yesterday Bill Clinton tried to turn down the temperature, attributing his tone to a desire to protect his spouse, and telling Harlem churchgoers: “We overdid it, putting too many nonviolent offenders in jail too long.”

“He remains the best political strategist and communicator in the party. But like any husband or family member, sometimes the fact that you are so close makes you react a little more strongly,” said Steve McMahon, a Democratic strategist who advised Howard Dean’s 2004 White House bid.

South noted that there is no playbook of how a former president should campaign for his spouse’s campaign because it’s never happened before.

Still, South said, “I don’t care if it’s a spouse, or if it’s a union leader, or a daughter or anyone else. Whoever it is who is surrogating for a candidate has be very careful that they don’t become the news.”