With incumbent Rep. Nancy Mace running for governor, South Carolina's 1st Congressional District Republican primary on June 9 remains wide open in a crowded field, where trader consensus favors state Rep. Mark Smith at 48% implied probability due to his early August 2025 campaign launch, third-term legislative experience from District 99, and local Daniel Island business ties providing name recognition and fundraising momentum. Retired Air Force Lt. Col. Alex Pelbath trails at 22%, buoyed by his high-profile military service piloting the last U.S. plane out of Afghanistan and recent March filing as a Trump-aligned conservative appealing to national security voters. Candidate filing closed March 30 without major disruptions, while a GOPAC spotlight on Smith last week reinforced his frontrunner status amid sparse primary polling; upcoming forums and debates could shift the closely contested dynamics.