Former congressman Joe Walsh has a "simple answer" about why President Obama "hates Israel:" Obama is secretly Muslim.

"For the past week, everybody has been asking again why Obama hates Israel," the former Illinois lawmaker and radio talk-show host tweeted Thursday, a week after the Obama administration's controversial decision to allow a United Nations resolution to pass that condemns Israeli settlement building as a violation of international law.

"The answer is simple really: I think Obama is Muslim," Walsh said.

"I've been saying that for awhile now. It makes the GOP uneasy when I say he's a Muslim. It makes my radio stations uneasy when I say it. I say it because I believe it."

Walsh said other radio talk show hosts and members of Congress, along with Fox News personalities, believe that Obama is Muslim in private but are too afraid to say it publicly for fear of losing ratings.

"For better or worse, I'm not afraid to say it publicly. I think Obama is Muslim. I think in his head and in his heart he has always been," Walsh said. "And I think it explains Obama's hatred toward Israel and explains his weakening of America these past eight years. It's not complicated."

"Under @BarackObama, Iran gets a deal and Israel gets screwed," Walsh continued. "Face it: Obama hates Israel."

Walsh's tweets echo one charge of the birther movement, which sees the president as a foreigner and perhaps a Muslim in disguise. President-elect Trump also fanned the flames of the popular conspiracy theory, becoming one of the movement's leading voices during the run-up to the 2012 election. Trump has since said he doesn't believe that. Obama says he is a Christian and openly celebrates Christian holidays and attends church.

Walsh has a history of making controversial statements about Muslims.

Last December, after the San Bernardino, Calif., terrorist attack, in which investigators say the shooters were radicalized and inspired by Islamic terrorists, Walsh said in an edited Facebook post: "Islam, as practiced by most Muslims, is not a religion of peace, and all of us who do live in peace should do whatever we can to defeat Islam."