On Monday, Iowa holds the first contest in the Republican presidential nominating process and nobody will have more on the line than Ron DeSantis. The Florida governor staked his candidacy on a victory in Iowa, a victory that now seems increasingly remote. Shane Goldmacher, a national political reporter for The Times, and the Daily producers Rob Szypko and Carlos Prieto explain what Mr. DeSantis’s challenge has looked like on the ground in Iowa. Guest: Shane Goldmacher, a national political correspondent for The New York Times.