Nearly two-thirds of Iowans, including 43 percent of Republicans, would like to see a strong challenger to President Donald Trump emerge in the Republican caucuses.Overall, 63 percent of Iowa registered voters told the University of Iowa’s Hawkeye Poll they want to see someone challenge Trump from within his own party.A majority of Republicans, 53 percent, isn’t interested in a Trump challenger, but 43 percent were open to a challenger.At least three Republicans have tested the waters, but none has mounted a significant campaign to win the GOP 2020 presidential nomination.Former Massachusetts Gov.