OXON HILL, Md. — President Trump said on Saturday that he planned to issue an executive order that would help guarantee free speech at colleges and universities by putting their federal aid at risk if they do not protect the viewpoints of students of all political stripes.

The president made the announcement during a rambling two-hour speech to activists at the Conservative Political Action Conference outside Washington, but he did not provide any details about the possible executive order. Several White House officials did not respond to emails or telephone calls seeking additional information.

The White House did not respond to questions about when the president might sign the order.

The issue of free speech on college campuses has for years been a cause célèbre among young conservative activists, who point to instances around the country in which conservative voices have been shunned by liberal students and professors.

The crowd, which included many college-age conservatives, welcomed Mr. Trump’s announcement, leaping to their feet when he pledged to hold school administrators accountable for ensuring that conservatives were permitted to express their views on campuses, often places where liberals outnumber them.