An abortive rally and an expanding field of challengers hasn’t hurt Donald Trump’s standing in Iowa, according to a new poll from Emerson College. In results released Thursday morning, 62% of Republican voters indicated they would choose Trump as the party’s nominee, giving the former president a 3-to-1 margin over Florida Gov. Ron DeSantis, who clocked in at 20%. Mike Pence and Nikki Haley are tied for third with 5%. DeSantis, who formally declared his run Wednesday during a Twitter livestream with Elon Musk, has long been considered the most significant challenger to Trump for the GOP nomination, but the...