(CNN) -- A spokesman for Ron Paul's presidential campaign said Friday that the Texas congressman is ending his run for the White House.

Rep. Ron Paul (R-Texas) ran for president as a Libertarian in 1988.

"We are acknowledging that Ron will not be the nominee and that we are winding down the campaign," said Jesse Benton, the Paul campaign's communication manager.

Paul hinted the end was near in a video to supporters posted on YouTube on Thursday.

"Though victory in the conventional political sense is not available in the presidential race, many victories have been achieved due to your hard work and enthusiasm," Paul said in the video.

His comments came two days after Sen. John McCain became the presumptive GOP nominee.

Former Arkansas Gov. Mike Huckabee, announced Tuesday he was quitting the race after McCain victories in Tuesday's primaries, leaving Paul as his only opponent.

Benton said the campaign encourages supporters to continue to take part in primary process and that Paul would honor requests from supporters to speak.

"We still think we can influence the debate and build an organization moving forward that brings the GOP back to its roots," Benton said.

Paul, who ran for president as a Libertarian in 1988, is the sole Republican candidate to call for a U.S. withdrawal from Iraq. He is a distant fourth in the GOP delegate count, behind McCain, Huckabee and former Massachusetts Gov. Mitt Romney.

"We must remember, elections are short-term efforts," Paul said. "Revolutions are long-term projects."

Paul's "Hope for America" campaign has been a grassroots effort, focusing on a "limited constitutional government, low taxes, free markets, and a return to sound monetary policies," according to his Web site.

"But even with the past year's achievements, we're still the early stages of bringing about the changes that this revolution is all about." E-mail to a friend

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