NASHVILLE (AP) — A federal judge in Nashville on Monday dismissed a challenge to a Tennessee law aimed at making sure primary voters are "bona fide" members of the party they are voting for.

Former Ambassador to Poland and longtime Tennessee Republican politician Victor Ashe sued state election officials in November, claiming the law is so vague that he could be prosecuted for voting in a Republican primary.

A law passed last year requires polling places to post warning signs stating that it's a crime to vote in a political party's primary if you are not a bona fide member of that party. Those signs refer back to a 1972 state law that has rarely been invoked. It requires primary voters to be "bona fide" party members or to "declare allegiance" to the party.

Because Tennessee voters are not registered by party, Ashe and other plaintiffs argued the laws invites arbitrary enforcement and are likely to intimidate otherwise legitimate voters. The laws do not define what it means to be a bona fide party member or to declare allegiance to a party, and they don't say how long that allegiance must last.

On Monday, U.S. District Judge Eli Richardson dismissed the lawsuit, ruling that Ashe, real estate developer Phil Lawson, and the League of Women Voters of Tennessee lack standing to sue. Richardson found that their claims of potential injury were too speculative.

Ashe and Lawson claimed they might be prosecuted for voting if officials doubt their party membership. Ashe is a Republican who routinely criticizes his fellow Republicans in a weekly column for the Knoxville News-Sentinel. Lawson is a Democrat who has also voted for Republicans and made financial contributions to Republican candidates.

The League of Women Voters of Tennessee had different concerns. The civic organization that helps register voters said it doesn't know how to accurately inform them about the primaries without subjecting them to potential prosecution. The league also worried that volunteers could be subject to a separate law that punishes people who promulgate erroneous voting information.

"The League does not adequately explain why a law that has been on the books for over 50 years is likely to suddenly confuse or intimidate voters," Richardson wrote.

The judge also found the defendants in the lawsuit — Tennessee Secretary of State Tre Hargett, Coordinator of Elections Mark Goins and Attorney General Jonathan Skrmetti — lack the power to prosecute violations of the challenged laws, so enjoining them not to enforce the laws would not help the plaintiffs.

Ashe said their attorneys are reviewing the ruling and will decide on next steps.

"My hope is that people still vote in the primary of their choice, and this doesn't reduce voter turnout," he said in a Monday phone interview.

Tennessee voters often decide which primary to participate in based on campaign developments. The partisan balance in Tennessee means many local elections are decided in the primary, with the large cities leaning heavily Democratic and most other areas leaning heavily Republican. It is not uncommon for people to vote for one party in local elections and a different party in federal or statewide elections.

Republicans, who control the Tennessee legislature, have discussed closing primaries for years, but the idea is controversial and has never had enough support to pass.