News broke Tuesday morning that retired pediatric neurosurgeon Ben Carson now leads the Republican presidential field not only in Iowa but also in a national New York Times/CBS News poll. And that means just one thing for Wednesday night’s debate in Boulder, Colorado: Carson will be under fire. How the GOP race’s newest front-runner fields the attacks will offer another angle on a candidate who is only beginning to face real scrutiny. Carson is known for his calm, soft-spoken demeanor. Over the course of his acclaimed surgical career at Johns Hopkins Medical Center in Baltimore, he earned the moniker “Gentle...