Billions are being wasted and the American economy is suffering at least in part because of gay marriage, a NOM speaker in Iowa asserted Sunday.

About 100 people gathered at the Iowa Statehouse to attend the National Organization for Marriage's (NOM) Summer for Marriage Tour 2010 anti-gay marriage rally.

The nation's most vociferous opponent of gay marriage has mounted a 23-city bus tour to promote marriage as between “one man, one woman.” The tour is expected to end with a Washington D.C. rally on August 15.

Iowa became the first – and remains the only – Midwestern state to legalize gay marriage when the Iowa Supreme Court unanimously ruled in favor of advocates last year. The issue is driving many of the state's top races, with several Republicans openly campaigning in favor of a constitutional amendment to define marriage as a heterosexual union.

Several attempts to begin the amendment process have been blocked by Democratic leaders in the Legislature, angering social conservatives opposed to the institution.

Representatives from two of the state's most vocal groups opposing marriage equality spoke to the crowd.

Danny Carroll, a former Republican legislator and chairman of the Iowa Family Policy Center, reminded the crowd to vote for anti-gay marriage candidates.

“Were you ever invited to a public hearing on the policy on marriage?” he asked. “No. But all political power is reserved to the people. You will have the opportunity to express your opinion at the ballot box this fall.”

The group met with some success backing a fiery social conservative for governor, Bob Vander Plaats, who promised to end gay weddings in the state at any cost. In the end, Republicans nominated former governor Terry Branstad, a moderate Republican who opposes gay marriage but has placed much less of an emphasis on repeal.

Tamara Scott, director of the Iowa chapter of Concerned Women for American, framed the gay marriage debate in terms of dollars and cents.

“It costs you, the taxpayer, as high as $280 billion a year for fragmented families, according to the Family Research Council,” Scott told the crowd, referring to a 2009 study from the social conservative group.

“If we would correct the breakdown of the family by 1 percent, we could save the taxpayer $3 billion a year. … We can fix this economic downturn very easily by fixing some hearts,” she added.

Studies by the Williams Institute at the UCLA School of Law, however, show that gay marriage has been a boom for states that have legalized it. A 2008 study estimated that the institution would generate $160 million for Iowa through 2011.

Two miles down the road, nearly 300 gay marriage supporters attended a counter protest organized by the gay rights group One Iowa.

Attending the rally was First Lady Mari Culver, who told the Iowa Independent that she disagreed with Scott's view of how gay marriage impacts the economy.

“I think [NOM] is looking for some economic cover, rather than reveal that some in their group are simply anti-gay,” she said.

The bus rolls into Sioux City on Tuesday.