A three-judge panel of the 9th Circuit U.S. Court of Appeals on Tuesday refused to reinstate Washington's "top-two" primary system, saying it infringes on the rights of political parties to choose their own nominees.

The top-two system was ruled unconstitutional last summer — before it was ever used — by U.S. District Judge Thomas Zilly. The state attorney general's office and the Washington State Grange asked the appeals judges to overturn that decision.

Voters approved the top-two system as Initiative 872 in 2004, a year after the state's nearly 70-year-old "blanket primary" was struck down. Like the blanket primary, the top-two system allowed voters to pick their favorite candidates for each office, regardless of party. But instead of the top Republican, Democratic and third-party candidates advancing, the top two vote-getters advance — even if they're both Republicans or both Democrats.

The trouble with the system is that it allows candidates to list their party on the ballot, without any input from the Republicans, Democrats or others about whether they want to be associated with those candidates.

The political parties challenged I-872 because they did not want anyone except their members picking their standard-bearer. The appeals court unanimously agreed that I-872 violated their First Amendment rights.