Republican opponents of the nuclear deal with Iran, facing likely defeat in Washington, are now aiming to keep economic sanctions in place at the U.S. state level.
Fifteen Republican governors, including four presidential candidates, said they would retain their state sanctions on Iran, while other Republican groups plan to try to take the issue directly to voters in state referendums in the November 2016 elections.
Roughly half of the 50 U.S. states have enacted measures that punish companies if they do business with Iran.
Congress on September 8 began debating the agreement, which would offer Iran relief from international sanctions in exchange for curbs on its nuclear program.
Republicans overwhelmingly oppose the deal, but President Barack Obama has secured enough support among Democratic lawmakers to ensure it survives congressional review.
The Republican Party's control over many statehouses gives the GOP an alternative to fall back on. In a letter to Obama, 15 Republican governors said their state sanctions "are critically important and must be maintained."
Four of the governors are competing for the Republican presidential nomination: Bobby Jindal of Louisiana, Chris Christie of New Jersey, John Kasich of Ohio, and Scott Walker of Wisconsin.
But Republican governors could encounter difficulties if they keep their sanctions against Iran in place.
State sanctions so far have done little to influence U.S. corporate behavior, and they can actually backfire by causing businesses to invest elsewhere, said Richard Nephew, a former U.S. sanctions official.
"They can just move to the state next door. Kentucky's loss can be Tennessee's gain," he said.
Though the impact of state sanctions is relatively minor for most businesses with operations in Iran, the issue was significant enough to be a negotiating point in the nuclear talks.
One paragraph in the final agreement, reached on July 14, directs the United States to "actively encourage" state and local officials to lift their sanctions.
Meanwhile, a group of Republican state officials operating under the name Defund Iran said it would try to put referendum initiatives on the ballot to strengthen sanctions in up to 25 states. That could potentially help their party's presidential nominee if it drives opponents of the deal to the polls to vote on the initiatives.
The Defund Iran campaign is initially targeting Arizona, Colorado, Florida, Missouri, and Ohio, but organizers say they hope to pursue similar measures in as many as half the states.
Ohio Treasurer Josh Mandel, who is honorary co-chairman of the group, said the effort would help ensure "that the radical Islamic regime in Iran is brought to its knees."
"I think we can both keep the tax money and the pension money away from terrorist-sponsored nations and also make a good return on behalf of the taxpayers," he said.
With reporting by Reuters and AP