DES MOINES — They heard a paean to the newly planted corn “when hope springs eternal.” They heard a promise to launch a drone attack on any American thinking of joining the Islamic State. They heard a candidate noting this was his latest stop on “the rubber-chicken circuit.”

More than 1,300 Republican stalwarts at the Iowa state party’s Lincoln Dinner listened to the biggest field of 2016 presidential hopefuls to visit the state so far. In tightly paced speeches of 10 minutes each, 11 contenders displayed the broad spectrum of ideologies and personal styles in the party’s unsettled, chaotic race.

The retired neurosurgeon Ben Carson, whose supporters had bought nearly a dozen tables at $750 apiece, delivered one of the most unusual speeches, describing an operation on an unborn twin whose head was dangerously swelling, meant to show his ability to solve problems despite his lack of governing experience.

The formally dressed crowd was more subdued than the audiences at gatherings of specialized interests such as evangelical Christians. The crowd never came to its feet during the evening. Red-meat lines that draw whoops in other rooms fell flat in a cavernous convention center ballroom in downtown Des Moines.