DES MOINES - A top legislative Democrat said Thursday western Iowa conservative U.S. Rep. Steve King doesn't have the courage to run for governor in 2010 because he knows he would lose to Democratic Gov. Chet Culver.

"Steve King is too chicken to run for governor because he knows he would get his butt beat," Senate Majority Leader Mike Gronstal, D-Council Bluffs, told reporters during an impromptu news conference in the hallway outside his third-floor Capitol office.

King, who was traveling in Iowa, fired back.

"Sen. Gronstal is afraid to allow a vote on marriage," King said, referring to the ongoing drama in the Legislature Thursday over bipartisan attempts to put a constitutional amendment to ban same-sex marriages in front of voters. Gronstal has vowed to bar any attempt to put the issue on the ballot.

King, who served in the Iowa Senate with Gronstal before being elected to Congress, said recently the Iowa Supreme Court decision effectively making same-sex marriages legal in Iowa may prompt him to run for governor next year. The decision, he said, makes it more likely he will run for governor.

If he enters the race, he won't be alone. Sioux City businessman Bob Vander Plaats is making his third attempt to win the GOP nomination. Rep. Christopher Rants, R-Sioux City, former speaker of the Iowa House, also has indicated an interest. Like King, Rants said the court's decision makes it more likely he will challenge Culver.

In criticizing the Supreme Court decision, King, a Kiron Republican, said Iowa lawmakers should adopt a residency requirement for marriage licenses so same-sex couples from other state don't come to Iowa to get married.

"Maybe we ought to have a residency requirement for congressmen, because he's gone a lot," Gronstal said.

Contact James Q. Lynch at (319) 398-8375 or james.lynch@gazcomm.com.