The clock is ticking on Rep. Thomas Massie (R-KY) to convince Kentucky he deserves another term in the House, as he engages in a duel with former Navy SEAL Ed Gallrein to secure the state’s Republican nomination. Voters head to the polls Tuesday to cast ballots in the race that decides who will head to the general election in November to represent Kentucky’s 4th District. Three recent polls have Gallrein in the lead or in a dead heat with Massie ahead of the Tuesday primary; another has Massie with a slim advantage.

“Massie continues to hold a durable base of support, especially among Republicans drawn to his independent brand and willingness to break with party leadership,” a Quantus Insights poll published this month reads. “But in a primary shaped heavily by [President Donald] Trump’s endorsement, national attention, and outside spending, Gallrein’s lead on both the initial ballot and leaner allocation shows the Trump-backed challenger in the stronger position entering the final stretch.”

Massie has warned that the race’s outcome will boil down to voter turnout and has sparked controversy for blaming donor funding from Israel supporters and lobbyists for fueling Gallrein’s campaign. He told the Washington Examiner over the weekend that he believes the race is “the most expensive in history, like anywhere.” According to AdImpact, $32.6 million has been poured into the race, the most expensive House primary on record.