After a well-received January appearance before a high-profile gathering of conservatives there, and several recent scraps with reporters, the new Quinnipiac University Poll put Walker, the Wisconsin governor, at 25 percent among likely participants in next year's Iowa Republican caucus. That total was nearly twice as much as the second-place finisher, Kentucky Sen. Rand Paul who drew 13 percent. Former Arkansas Gov. and 2008 caucus winner Mike Huckabee (at 11 percent), fiery surgeon Ben Carson (also 11 percent), and former Florida Gov Jeb Bush (10 percent) were the only other candidates who attracted backing from more than five percent of...