WASHINGTON — (CNN) In a sign that the legal team for the Trump campaign is aggressively laying the groundwork for potential legal challenges — big and small — lawyers have gone to state court in Nevada in an early vote dispute.

They are suing Joe P. Gloria, the Clark County registrar of voters, over a decision they allege he made to keep polling locations open “two hours beyond the designated closing time.” The lawsuit targets polling places in the greater Las Vegas area that have larger minority voting precincts.

Dan Kulin, a spokesperson for the county, told CNN that no early voting stations extended their closing times.

They did, however, process voters who were in line at closing time to allow as many people to vote as possible.

In legal briefs filed Monday night, Trump lawyers are asking for an order to have the pertinent early vote ballots not to be “co-mingled or interspersed” with other ballots

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“From the polling, it appears that Nevada is so close that the Trump campaign thinks it’s worth challenging any violation in voting protocol. The numbers that came in could represent several thousand people across the four precincts, which could determine who wins the electoral college vote or change the Senate race,” said Robert Lang of the University of Nevada, Las Vegas.

He said the Trump campaign is “smart to put a marker down for a future challenge, considering what happened in 2000 in Florida.”

Officials with the Republican National Committee and Trump’s campaign declined to further discuss their action with reporters on a conference call early Tuesday afternoon.

Nevada’s Republican Party chairman, Michael McDonald, told a Trump audience in Reno on Saturday that polling locations were kept open late so that a “certain group” could vote.

“Last night, in Clark County, they kept a poll open ’til 10 o’clock at night so a certain group could vote,” McDonald said in introductory remarks at a Trump rally.

“The polls are supposed to close at 7. This was kept open until 10. Yeah, you feel free right now? You think this is a free and easy election? That’s why it’s important.”

Clark County, which includes the suburbs of Las Vegas, has a large Hispanic population and could figure prominently in who wins the White House.

At Saturday’s rally, Trump suggested that the polling location’s extended closing time to allow voters to cast their ballots was a sign of a “rigged system” pitted against his campaign.

“It’s being reported that certain key Democratic polling locations in Clark County were kept open for hours and hours beyond closing time to bus and bring democratic voters in. Folks, it’s a rigged system. It’s a rigged system and we’re going to beat it. We’re going to beat it,” Trump said.