At-Large D.C. Councilmember and mayoral contender Robert White is aiming to keep fellow lawmaker Trayon White (D-Ward 8) off the ballot for June mayoral primary. It’s a potentially consequential move that if successful could set up a more direct battle between Robert White and Mayor Muriel Bowser, who is running for a third term.

Robert White announced Monday night that he is challenging a large number of the signatures that Trayon White submitted to get on the ballot; candidates have to collect 2,000 signatures from registered Democratic voters to qualify for the primary ballot. Along with Robert White, Trayon White, Bowser, and former Ward 5 ANC commissioner James Butler have submitted signatures to get on the ballot.

In a press release, White’s campaign said it found “significant discrepancies” in the more than 4,300 signatures that Trayon White submitted to the D.C. Board of Elections on March 23. The campaign is challenging roughly 2,800 of White’s signatures.

“This is a moment when we need a leader who will bring all the wards of our city together and effectively manage a $20 billion budget to solve the big problems facing our residents,” said Robert White. “We have had eight years of government mismanagement that has cost us millions of dollars. I am running this campaign with the same due diligence and focus on execution that I will bring to office as mayor.”

Trayon White’s campaign did not respond to an email about the challenge, but he told the Washington Post he believes it to be “weak.” Ari Theresa, an attorney who helped Trayon White collect signatures, criticized Robert White’s challenge in a tweet earlier this week.

“So [Robert White] and all the dole he got from [gentrifiers] and white-run non-profits is using his ‘access’ to challenge the signatures of DCs Black and poor residents but I’d say it’s par for the course and why the vote between the ‘advocates’ and the people advocated for is split,” he wrote.

D.C. law sets specific thresholds for the number of voter signatures candidates for different offices have to collect in order to get on the ballot. It also specifies voters must list their address, which has to match what the elections board has on file. Voters who sign also must be of the same party as the candidate participating in a primary. People who collect the signatures have to be D.C. residents, and if they’re not, they have to be registered with the elections board.

Robert White’s campaign is challenging Trayon White’s signatures on a number of grounds, including that some of the signers either aren’t registered Democrats or aren’t registered at the address they listed on the nominating petitions. The campaign is also challenging the residency of some of Trayon White’s petition circulators, which could lead to entire sheets of signatures being declared invalid.

Challenging nominating petitions has a long history in D.C., and has fully derailed some candidacies.

In 2002, then-mayor Anthony Williams was famously tossed off the ballot when it was revealed that many of the signatures his campaign submitted were fraudulent. (He ended up running as write-in candidate — and won.) More recently, in 2018 Councilmember Elissa Silverman (I-At Large) had a pro-business challenger denied a spot on the ballot by successfully challenging the validity of their signatures. Efforts to put voter initiatives on the ballot and also efforts to recall sitting councilmembers have also been cut short when proponents had their signatures challenged.

Keeping Trayon White from getting on the ballot for the June primary would be consequential for Robert White, largely because as the race currently stands he and his fellow lawmaker risk splitting the vote and letting Bowser cruise to a relatively easy third term. A poll conducted by the Washington Post in February — the only public poll of the race thus far — found Bowser getting support from 47% of registered Democrats, with Robert White and Trayon White virtually tied, with 19% and 17%, respectively. (Robert White has been more successful in fundraising, with more than $800,000 in the bank as of last month. Trayon White, by comparison, had roughly $22,000.)

Similar challenges have been filed in other races on the June ballot. In the contest for an At-Large council seat, candidate Lisa Gore is challenging the signatures submitted by fellow contender Leniqua’dominique Jenkins, who is also facing a challenge from former Ward 2 ANC Commissioner James Harnett. Dennis Jaffe, Gore’s campaign advisor, is also challenging the signatures submitted by At-Large candidate Bradley Thomas, who also faces a challenge from candidate Nate Bennett Fleming. And Fleming is also challenging fellow candidate Dexter Williams. There are six candidates running for the At-Large seat, including incumbent Anita Bonds.

In a separate challenge, candidate for D.C. attorney general Bruce Spiva has filed a formal complaint accusing fellow candidate and Ward 5 Councilmember Kenyan McDuffie of not meeting the qualifications for holding the office.

The elections board has until April 25 to rule on any challenges of signatures, though any candidate who comes out on the wrong end of that can still take the matter to court.