(CN) — Democratic voters living in the Florida Panhandle filed a lawsuit Tuesday arguing presidential hopeful Bernie Sanders should be listed as an independent candidate for the state’s May 17 primary because he’s not actually a Democrat.

Filed by veterans, longtime Floridians and lifelong Democrats Frank Bach and George Brown in Leon County Circuit Court, the complaint asserts that state law requires a candidate to run for the party with which they are affiliated.

In the filing written by Tallahassee-based lawyer Karen Gievers, they say keeping Sanders on the Democratic ballot will “adversely affect their right to have the Democratic presidential preference primary limited to those who are, in fact, Democrats.”

The complaint – which names as defendants Sanders, the Florida Democratic Party, Democratic National Committee and Florida Secretary of State Laurel Lee – also notes that the Sunshine State has a closed primary system, meaning residents have to be a registered member of a political party to vote in its primary.

“Defendant Sanders is clearly an Independent, and is clearly not a Democrat, by his own definitions,” the lawsuit states. “His current ‘day job’ is as a United States senator and he has consistently, proudly asserted his service in that role as Independent; he is one of two Independents identified as serving in the Senate.”

Bach and Brown also point to Sanders’ ongoing fundraising effort for his next Senate election, when he will again identify as an Independent. The lawsuit includes copies of the Vermont senator’s recent campaign finance data showing he’s raised a little under $1 million so far for his 2024 reelection bid.

“In this day and age of increasing disregard for the law, it is essential that the [plaintiffs have the] right to vote and select from true Democrats in the March 17 Democratic presidential preference primary without dilution of the effect of their votes,” the seven-page complaint states.

The two voters are asking a state judge to disqualify Sanders from the Democratic primary and prevent Secretary of State Lee from certifying any votes cast for the candidate.

For his part, Sanders signed a loyalty pledge in early 2019 promising to run and govern as a Democrat if he won the 2020 presidential election. The idea for the pledge is believed to have stemmed from his failed 2016 run, which similarly raised questions about his allegiance to the party. In exchange for signing the pledge, the Democratic National Committee agreed to change the way superdelegates impact the nomination process.

Bach and Brown are not alone in their concern with Sander’s party affiliation. On the debate stage, former South Bend Mayor Pete Buttigieg has often attacked the senator for his Independent affiliation, saying the party should instead “put forward somebody who’s actually a Democrat.”

While Buttigieg and the Florida voters might take issue with Sanders’ run, the candidate has obviously found a strong base among Democratic voters. He won the most delegates in the first three primaries with a resounding win in Nevada last weekend.

A 2019 Gallop poll shows the once-moderate Democratic Party appears to be shifting. About 50% of party members identified as moderate when President Bill Clinton was in office, but last year’s survey showed the same amount now identify as liberal.

Meanwhile, a Quinnipiac poll released earlier this month found all leading Democratic candidates had negative net favorability ratings, but Sanders’ was the best at -5. President Trump Donald came in at -13.

In an emailed statement, Sanders spokesperson Kolby Lee said the campaign was aware of the “spurious complaint” but that it will not impact the candidate’s designation in Florida’s primary.

“Bernie will be on the ballot in Florida,” Lee said.

But in a phone interview, the plaintiffs’ attorney, Grievers, stressed this wasn’t a politically motivated lawsuit, but rather an attempt to force the candidate to follow the rules.

“The law matters and peoples’ rights matter,” she said.