A Democratic presidential candidate who shocked some of his supporters by agreeing to speak at an upcoming convention of conservative parents rights activists now says he will be unable to attend. 

Robert F. Kennedy Jr. was due to speak at the Moms for Liberty summit at Philadelphia this week, but dropped out “for family reasons,” a press person for the campaign tells the Sun.

A Moms for Liberty co-founder, Tiffany Justice, dropped the news Tuesday, saying the Kennedy campaign “told us his schedule changed and he can no longer speak to our summit.” The group had been advertising Mr. Kennedy’s appearance, but his name is now removed from the schedule.

Several Republican presidential hopefuls are planning to speak at the group’s annual convention, which starts Thursday. President Trump is headlining the event on Friday. Governor DeSantis and a former U.N. ambassador, Nikki Haley, are also scheduled to speak Friday. A biotech entrepreneur, Vivek Ramaswamy, and the former Arkansas governor, Asa Hutchinson, will also speak.

An environmental lawyer best known now for his vaccine skepticism, Mr. Kennedy is intentionally reaching out to voters on both sides of the aisle. His anti-interventionist foreign policy and critiques of the nation’s Covid response and government and tech censorship are attracting throngs of Republicans and independents to his events. Mr. Kennedy spoke last week at the libertarian Free State Project’s annual festival in New Hampshire, defying calls from the state’s Democratic Party chairman to stay away from the “dark, dystopian” group.

“Both parties have lost their way,” Mr. Kennedy said on Joe Rogan’s podcast. “My campaign is about bringing those two groups together — the left and the right — in a populist movement.”

Moms for Liberty, though, may have been a bridge too far.

The Southern Poverty Law Center designated Moms for Liberty an “extremist group” earlier this month, calling it “hard-right” and anti-LGBTQ.

“Schools, especially, have been on the receiving end of ramped-up and coordinated hard-right attacks, frequently through the guise of “parents’ rights” groups,” the SPLC’s “Hate and Extremism” report states. “At the forefront of this mobilization is Moms for Liberty. … The group’s primary goals are to fuel right-wing hysteria and to make the world a less comfortable or safe place for certain students — primarily those who are Black, LGBTQ or who come from LGBTQ families.”

A “hate” designation from the SPLC, though, has lost its weight in recent years. Along with neo-Nazis and the Ku Klux Klan, the SPLC labels immigration reform groups such as the Dustin Inman Society hate groups, and even included a Somali survivor of genital mutilation, the author Ayan Hirsi Ali, on its anti-Muslim hate list. It has also called a religious freedom nonprofit law firm, the Alliance Defending Freedom, which has argued several cases before the Supreme Court, a hate group. The designation often just means conservative. 

Moms for Liberty was founded in 2021 by three current and former Florida school board members concerned about Covid closures and mask mandates in schools. Since then, the group has shifted its focus to fighting critical race theory, gender ideology, and LGBTQ lessons in schools. “We don’t co-parent with the government” is one of the group’s slogans.

In a little more than two years, Moms for Liberty has become a potent force in Republican politics. Mr. DeSantis embraced the group early on and spoke at its 2022 summit in Miami. One of the group’s three founding mothers, Bridget Ziegler, who has since left the organization, is the wife of the vice chairman of the Florida Republican Party. They’ve been vocal supporters of Mr. DeSantis’s “Parental Rights in Education” bill — dubbed “Don’t say gay” by the left — and of his crackdowns on race and gender curricula in schools.

There are more than 280 Moms for Liberty chapters in 44 states. The group has helped elect school board members, push legislation, ban sexually explicit books, and mobilize a sizable base of concerned parents to vote. It has become the preeminent conservative group fighting the culture war with regard to children.

Moms for Liberty has said it will not endorse a candidate in 2024. Republican candidates, though, are flocking to the event — a showcase of the group’s political influence.

Before Mr. Kennedy dropped out, he was attacked in the press about his upcoming appearance at the Moms for Liberty conference. “Why is Kennedy, who purports to care about issues of censorship, speaking at the summit? Perhaps because he’s running on the wrong ballot,” an article in the New Republic declared.

A group of Pennsylvania state senators is urging the Museum of the American Revolution, which is hosting the Moms for Liberty event, to cancel it. They call Moms for Liberty a “hate group.” The contents of the letter appear borrowed from the SPLC’s writings on the group.

“Moms for Liberty are absolutely not a hate group & attempts to shut them down is due to their effectiveness,” conservative columnist Karol Markowicz tweeted. “But how is it not a violation of their First Amendment rights that elected officials are trying to get their event canceled?”