Prepping for 2016, a Gathering of Republicans in Iowa Leans Hard to the Right

A crowded field of potential Republican presidential candidates scrapped for the hearts of the party’s conservative base here Saturday, implicitly rejecting the more moderate wing favored by big donors and trying to fire up the kind of grass-roots supporters who will play a critical role in the nominating process.

The daylong forum, billed as an informal kickoff to the 2016 campaign, was attended by about 1,200 people, many of whom ardently oppose the centrist views that tend to prevail in a general election.

The speakers, some of them experienced presidential campaigners, came to test and tweak their messages, to seek second chances and to introduce themselves to voters wh