David Roth commands 91% implied probability in the Idaho Democratic U.S. Senate primary on May 19, driven by his established profile as a business leader, DNC member, and 2022 nominee against Sen. Mike Crapo, bolstering name recognition among limited Democratic and unaffiliated voters in the open primary. Recent endorsements from Madison County Democrats and the University of Idaho Federation of Teachers, alongside active campaigning as noted in voter guides this week, have solidified trader consensus on his dominance over challengers Brad Moore and Nickolas Bonds, who lack comparable party support or visibility. Upsets remain possible via a late scandal, opponent surge in final absentee voting, or unexpected crossover turnout, though historical low Democratic primary participation in Idaho favors the frontrunner.