Former Harvard President Lawrence Summers took the university's leadership to task for refusing to stand against antisemitism in an essay posted on X Tuesday, saying it had been the "worst stretch" in its storied history.

"My confidence in Harvard leadership’s ability and will to confront anti-semitism and the demonization of Israel continues to decline," Summers wrote. "Unfortunately, it is becoming ever clearer why Harvard ranks first on anti-semitism, even as it ranks last on upholding free speech."

Summers, who also served as Secretary of the Treasury under President Clinton and as director of the National Economic Council under President Obama, argued that free speech still allows for stopping antisemitism on campus.

FORMER HARVARD PRESIDENT LARRY SUMMERS HAS 'LOST CONFIDENCE' IN SCHOOL'S CURRENT LEADERSHIP

"Confronting anti-semitism does not mean punishing offensive speech as some suggest," Summers wrote. "Free speech is sacrosanct in a university. But effective leadership does involve assuring the appropriateness of speech made by the university and its subunits and it means encouraging speech that counters prejudice and balances debate." 

Summers' statement included disappointment at what he said were no "new initiatives directed at education on antisemitism or the Holocaust" and no invitations to pro-Israel voices.

Accusations of antisemitism have rocked Harvard for months, with its former President, Claudine Gay, resigning from her position on Jan. 2 after she gave widely criticized testimony in front of Congress and faced dozens of allegations of plagiarism. 

Gay's historic resignation made her the shortest serving president in Harvard's history. 

BILLIONAIRE HARVARD ALUM BILL ACKMAN IS NOT DONE PUSHING FOR CHANGES AFTER PRESIDENT'S RESIGNATION

Summers praised Gay for resigning after initially lending her support in December. 

"I admire Claudine Gay for putting Harvard's interests first at what I know must be an agonizingly difficult moment," Summers wrote on the day of Gay's resignation. "Alan Garber, who is universally liked, admired, and respected, is a superb choice as Interim President. At this complex juncture, there will be much to reflect on as Harvard sets its course forward."

Since then, Summers has repeatedly called out Harvard — and especially the school's leadership — for not doing enough to combat antisemitism on campus. 

"I cannot think of a worse stretch in Harvard history than the last few months," he wrote. "I have no doubt that all members of the Corporation are deeply devoted to Harvard. As the institution’s ultimate fiduciaries, I hope they will take appropriate accountability and enable a restoration of confidence."

Overall, he wrote that he was hopeful for change at Harvard. "The challenges are real but resolvable," he wrote. "Harvard is blessed with an extraordinary collection of students, faculty and staff and abundant resources. The mission of seeking truth and educating leaders has never been more important. This is a moment for wisdom and boldness."

GET FOX BUSINESS ON THE GO BY CLICKING HERE

Harvard didn't respond to FOX Business' request for comment.

Fox News' Andrew Mark Miller contributed to this report.