DES MOINES — The 2016 Republican race has an unprecedented number of candidates who have run for president before. In the 2008 field of a dozen candidates, just two — the ultimate nominee, John McCain, plus Ron Paul, who ran as a libertarian in 1988 — had run before. In 2012, two candidates — the nominee, Mitt Romney, plus the perennial Paul — had previously been around the track.

This time, four candidates — Rick Santorum, Mike Huckabee, Rick Perry, and Romney — have run for the White House. In addition, another candidate, Jeb Bush, is a first-timer with a last name that’s been on the presidential ballot in 1980, 1984, 1988, 1992, 2000, and 2004.