As a major rally prepares to descend Tuesday on Des Moines to protest Iowa Senate President Mike Gronstal's vow to block a constitutional amendment banning gay marriage from coming up for a vote in the Senate, Gronstal on Sunday stood by his decision.

The measure, which would overturn the Iowa Supreme Court's unanimous 2009 ruling legalizing gay marriage, won easy passage in the Republican-controlled House last year. But Gronstal, a Democrat, blocked the measure from reaching the Senate floor, angering social conservatives who have threatened to oust him.

The National Organization for Marriage (NOM), The Family Leader and CatholicVote.org have been busy for months promoting the Let Us Vote! (LUV) rally in emails to supporters, and expectations are high for a decent crowd.

“Yes we want to put pressure on Senator Gronstal,” Bob Vander Plaats of The Family Leader said in a video promoting the rally. “And we need you to tell your senator to tell Senator Gronstal to let it come up for a vote.”

In remarks to blogger AKSARBENT, Gronstal reiterated his position on the amendment.

“We never put people's constitutional rights to a vote of the people in this state. I don't think the constitution is the place to insert discrimination. I think it's a document designed to guarantee people's rights, not to take them away from them,” Gronstal said. (The video is embedded in the right panel of this page. Visit our video library for more videos.)