The chairman of the American Conservative Union endorsed Mitt Romney for president Thursday, saying the former Massachusetts governor is the best hope for conservatives in 2008.

David Keene said in a statement that he intends to spend the coming weeks persuading other conservatives to close ranks behind the GOP candidate, who has also earned the support of Moral Majority Co-Founder Paul Weyrich.

"As this race began, I intended to remain neutral both because there was no conservative consensus candidate and because I know and admire several of those running for the Republican nomination who I believe could win next fall," Keene said. "In recent months, however, Governor Romney has emerged as the single candidate most worthy of conservative support."

Keene has been a national spokesman for conservative causes since the '70s, and frequently writes opinion pieces for various political publications.