Michael Katz leads the Delaware Republican U.S. Senate primary contest ahead of the September 15 vote, reflecting trader consensus on his prior elected service as a state senator and nomination at the state Republican convention after switching parties. John Shulli, an instructor at the U.S. Army War College with a military background, trails despite raising substantially more campaign funds through March. The two-candidate field has seen limited movement since filings concluded earlier this year, with no major new endorsements, polls, or events reported in recent weeks to alter positioning. Resolution hinges on the primary outcome, where Delaware's small Republican electorate and Katz's name recognition appear to anchor current implied probabilities.