Rachel Maddow on Monday called out three Republican presidential candidates for their participation in a “kill-the-gays” rally over the weekend.

Texas Senator Ted Cruz, Louisiana Governor Bobby Jindal and former Arkansas Governor Mike Huckabee took part in the National Religious Liberties Conference, which was organized by pastor Kevin Swanson, a Colorado-based Christian conservative who has previously called for the death penalty for homosexuality.

Swanson told attendees that he would protest a gay couple's wedding by smearing cow dung over his body and reiterated his call for the government to execute unrepentant gays in the future.

(Related: Kevin Swanson: Gays need time to repent before being put to death.)

Maddow pointed out that Swanson's extremist views on homosexuality were well known before this weekend's event.

“A pretty major theme of the event, both in terms of the literature that was available at the event and the way the host of the conference spoke from the stage, a significant theme was the practical challenges and the timing of how exactly and when exactly the United States of America should start rounding up gay people in this country in order to execute them,” Maddow told her MSNBC viewers.

“It really was a 'kill-the-gays' call to arms. This was a conference about the necessity of the death penalty as a punishment for homosexuality.”

Maddow wondered whether moderators at Tuesday's Fox Business GOP debate would ask the candidates about the event.

“I don't know if that is considered to be a scandal anymore in Republican politics,” she noted.

At the event, Huckabee and Jindal reiterated their opposition to marriage equality, with Huckabee saying that he would ignore the Supreme Court on the issue as president.

(Related: Mike Huckabee vows to ignore gay marriage ruling as president.)