Iowa candidates vying for the Republican Party's gubernatorial nomination are ratcheting up their anti-gay rhetoric and fulfilling a promise to make gay marriage a central issues in this year's race.

On Friday, Iowa State Representative Rod Roberts added the latest twist.

Appearing before a gathering of about 30 people at Jonesy's Taco House, Roberts said that if elected he would withhold his signature from the state budget until lawmakers agree to allow Iowans a vote on the issue.

Social conservatives are livid at Democrats, who control the Legislature, for blocking Republican-led efforts to begin the multi-year process to amend the Iowa Constitution. Before appearing on the ballot, the measure needs the approval of two consecutive sessions of the Legislature, making 2014 the earliest voters could see the measure at the ballot box.

“It's clear people want to weigh in on that discussion, and they should,” the Omaha World-Herald quoted Roberts.

The 52-year-old Roberts joins Sioux City businessman Bob Vander Plaats in promising to aggressively repeal gay marriage in the state.

Vander Plaats has pledged, if elected, to halt gay weddings with an executive order until the issue is decided by voters. Most analysts agree that such a move would exceed the governor's authority and could possibly lead to impeachment charges. His aggressive stance, however, has won him the endorsement of the state's most vociferous opponent of gay marriage, the Christian-based Iowa Family Policy Center (IFPC).

While all GOP gubernatorial candidates say they support defining marriage as a heterosexual union in the Iowa Constitution, only Roberts and Vander Plaats are promising strong-arm tactics to get the job done.

Saturday was the first anniversary of the unanimous Iowa Supreme Court decision that legalized the institution in the state.