Rahm Emanuel heads into a runoff April 7 in his bid for a second term as mayor of Chicago. He’s the favorite going in, having won 46 percent in the Feb. 24 first round against longtime local officeholder Chuy Garcia’s 34 percent and topping 50 percent in recent polls.

Emanuel, President Obama’s first White House chief of staff and architect of Democrats’ 2006 takeover of the House, is politically astute, energetic and profane. Given all that, it’s surprising that his support is down from the 55 percent he won in the first round in February 2011.