Gov. Gary Locke signed a bill Thursday creating a Montana primary election system, after vetoing part of the bill that would have created the so-called “top-two primary,” modeled after the Louisiana system.

“I must reiterate my extreme frustration and disappointment with the Republican and Democratic parties for challenging the constitutionality of the blanket primary in the first place,” Locke said. “The blanket primary has served our state well for almost 70 years.”

Locke had hinted at using his veto powers previously over the Louisiana system, and Thursday reiterated that the system “is a poor option for Washington voters” because “it limits voter choice and participation.”

“I have said all along that I support the Montana system because it best preserves the voter choice in the November general election,” Locke said.

In the Montana system, voters can choose among candidates from a single party in partisan races in the primary election, and could vote for anyone in the nonpartisan races.