John Locher, File, Associated Press
FILE - In this July 14, 2015, file photo, Republican presidential candidate Wisconsin Gov. Scott Walker speaks during a campaign event at a Harley-Davidson dealership in Las Vegas. Walker is scheduled to address an annual showcase of conservative activists, Thursday, July 23, in San Diego.

SAN DIEGO — Wisconsin Gov. Scott Walker has told a crowd of conservative state lawmakers from across the nation that if he's elected president, he would trash President Barack Obama's nuclear deal with Iran on his first day in office.

The Republican contender struck a combative tone Thursday at the American Legislative Exchange Council's annual meeting in San Diego.

Walker said Iran has changed little since it took Americans hostage in 1979 and that the U.S. shouldn't have negotiated the deal that eases sanctions in exchange for concessions on the Islamic nation's nuclear program.

He spoke on several other topics, including his clashes with organized labor.

ALEC promotes and writes business friendly legislation for use in state legislatures. Its proposals have included "right-to-work" measures that prohibit union membership as a condition of employment.