An opening prayer that shocked Minnesota House members on Friday may have unintentionally derailed a key goal of social conservatives this session: a constitutional amendment to ban same-sex marriage.

As protesters packed a hallway outside the House chamber in anticipation of a floor vote, controversial pastor Bradlee Dean stood at the House rostrum to offer an invocation.

Wearing a black-and-white track suit and sporting a ponytail, Dean offered a prayer that in part implied that President Obama was not a Christian. Dean referred to Jesus Christ as the "head of the denomination ... as every president up until 2008 has acknowledged. And we pray it in Jesus' name."

That prompted an immediate outcry from some lawmakers and a statement by House Speaker Kurt Zellers denouncing Dean, which he followed up with an emotional apology on the House floor.

Dean, who heads a ministry he calls "You Can Run But You Can't Hide," has caused uproars before, saying homosexuals should be jailed and making comments that appear to support their execution.

Friday's bombshell arrived just as legislators were prepping for a vote to put the amendment question on the 2012 ballot. While the vote had once seemed a certainty for this session, by Friday afternoon it was in serious doubt.

"We never said whether we are going to take it up or not," said Zellers, R-Maple Grove. Pressed on the timing of the vote, Zellers said: "At this point, I don't [know] and I'm not prepared to say." Zellers later said he still believes he has the votes to pass the amendment.

The Minnesota Family Council, advocates of the amendment, sent out an evening e-mail to its members, asking them to turn out at the State Capitol to apply pressure. The Legislature must adjourn its regular session by Monday at midnight.

The amendment already had a tough path. Public opinion has shifted against it and some GOP members planned to join most, if not all, Democrats in voting against it. A recent Star Tribune poll showed that a majority of Minnesotans oppose such an amendment and a national Gallup Poll released Friday showed that for the first time, most Americans -- 53 percent -- support same-sex marriage.

If supporters don't get the amendment passed by Monday, they may need to wait until next year. While lawmakers are certain to be called into special session by Gov. Mark Dayton because of a budget stalemate, he strongly opposes the amendment and would work to keep it off any special session agenda.

Former state Rep. Chris DeLaForest, R-Andover, counseled his colleagues that "anything you don't get to this year you certainly can get to next year." Some Republicans said privately Friday that the explosive reaction touched off by Dean's prayer was a sign they should delay the vote to 2012.

Tense mood

The mood in the House was tense even before Dean's prayer. As they have nearly all week, passionate opponents of the marriage amendment stood outside the House chamber, cheering their allies and chanting so loudly the sound echoed through every floor of the Capitol.

Once Dean finished, Rep. Terry Morrow, DFL-St. Peter, rose to say that the expected hope of peace in the daily prayer had been "crushed by a single person's words."

Decorum on the floor broke so badly that Zellers hit a session reset button. He asked the regular House chaplain, the Rev. Grady St. Dennis, to pray, then called for another Pledge of Allegiance and another attendance vote.

From the lowly members' well in the House, a stricken Zellers addressed his fellow House members. "That type of person will never, ever be allowed on the House floor again," he pledged.

In a separate statement, Zellers said of Dean, "I take responsibility for this mistake. ... I denounce him, his actions and his words. He does not represent my values or the values of this state." Zellers is a cosponsor of the marriage amendment.

Republicans and DFL members, the American Civil Liberties Union of Minnesota and even the pro-amendment Minnesota Catholic Conference joined in denouncing Dean and in backing the seeming official sanction from the House.

'I said a prayer'

Dean was unfazed.

"I said a prayer. If a prayer starts a firestorm, so be it," he said in a later interview.

He said it wasn't right to call him "anti-gay," but he spoke admiringly of the time when homosexuality was illegal.

"We don't enforce those laws anymore, and we wonder why we are going backwards," Dean said. "If you were to ask me my position as far as enforcing the laws of sodomy in the state of Minnesota, I would say absolutely yes. Yeah. Yeah."

Asked about Zellers' apology for allowing him to speak, Dean retorted: "I apologize for him being in the position he is in if he doesn't understand what I said."

It was a freshman legislator, Rep. Ernie Leidiger, R-Mayer, who had arranged the guest pastor's visit.

Leidiger said he was unaware of Dean's views on homosexuality, calling it "radical thinking -- that kind of thinking, I think back to Nazi Germany." Leidiger did say he liked Dean's message about "bringing the Constitution back" into the schools. "Little did I know there's another side of him, which, by the way, I just learned today," he said.

Republican ties

Other Republicans know Dean. Rep. Mary Kiffmeyer, U.S. Rep. Michele Bachmann and 2010 Republican gubernatorial candidate Tom Emmer all have been associated with him. Bachmann has fund-raised for Dean's group and is scheduled to share a stage with him at a Tea Party event, Freedom Jamboree, in September.

Some Democratic members were previously unaware of Dean's message.

Minneapolis DFLer Rep. Karen Clark was searching for Dean's history on the Web shortly after the pastor and radio show host left the floor.

She and Sen. Scott Dibble, both of whom are gay, jointly denounced Dean's presence. Clark called him "a hateful person" and said his appearance in the chamber was "reprehensible."

Rachel E. Stassen-Berger • Twitter: @rachelsb