Republicans have launched legal challenges in three battleground states over the past several weeks targeting the rules that govern ballots cast by U.S. citizens living overseas, including military personnel.

The lawsuits, filed in Michigan, North Carolina, and Pennsylvania, argue that current overseas voting regulations are vulnerable to election fraud, claims supported by former President Donald Trump and his allies. The challenges coincide with allegations raised about noncitizens voting by Trump and supporters such as Tesla founder Elon Musk.