WATCH: Duffy flips script on Dem senators with pointed questions about their own campaign cash

Transportation Secretary Sean Duffy turned the tables on two Democratic senators who accused him of allowing companies under his oversight to bankroll his "Great American Road Trip," firing back by highlighting donations they received from industries and groups tied to policies they regulate.

In celebration of America's 250th birthday, the bipartisan America 250 commission sanctioned Duffy's participation in a 10-state road trip with his family to encourage tourism. The expedition was funded...