It seemed like a straightforward question on a second-tier issue: Would Mitt Romney disavow the science behind global warming? The putative Republican presidential front-runner, eager to prove his conservative bona fides, could easily have said what he knew many in his party’s base wanted to hear. Instead, the former Massachusetts governor stuck to the position he has held for many years — that he believes the world is getting warmer and that humans are contributing to it. Romney’s answer to a question about climate change last Friday during his first town hall meeting since announcing his second presidential campaign allowed...