Donald Trump is taking sides in the intra-party GOP battle over Rand Paul's filibuster, saying Monday morning that the effort "did nothing" and amounted to little more than a protest.

"I happen to feel that the filibuster did nothing," Trump said during an appearance on "Fox and Friends." "They got nothing out of it. There was really nothing gained by it. It was just a protest, and we need more than protests."

GOP Sens. Lindsey O. Graham (S.C.) and John McCain (Ariz.) have also spoken out against the nearly 13-hour filibuster, with McCain going so far as to label Paul a "wacko bird."

Trump said Paul, who was trying to get the White House to say it would not use drone strikes against Americans on American soil, was asking a question that everyone already knew the answer to.

Attorney General Eric H. Holder Jr. issued a letter after Paul's filibuster clarifying that the United States would not use drone strikes on American soil against "noncombatant" U.S. citizens.

"Everybody knew that memo was essentially what was going to happen anyway," Trump said. "And many of the Republicans -- I have to tell you I'm friends with many Republicans -- and they were not happy with it at all."

The issue is likely to be a major subplot of this coming weekend's big conservative gathering in the Washington area, the Conservative Political Action Conference (CPAC). Both Trump and Paul are slated to speak.