BRIAN HUGHES: Obama paints himself into a corner over Trayvon Martin. “The president’s own words more than a year ago — “If I had a son, he’d look like Trayvon” — are fueling the push for his Justice Department to bring federal charges against Zimmerman, the Hispanic neighborhood watch coordinator who has become a symbol of a broken justice system in the eyes of civil rights groups. When Obama waded into the controversy in March 2012, his words seemed to carry limited consequences. His statement of support for the Martin family played well with supporters and was more than a year away from the polarizing trial. It’s not that simple any more. . . . Despite White House efforts to distance the president from the department’s investigation, Obama inevitably will have to answer for how his administration proceeds. The White House can ill afford to give critics more ammunition as the administration fends off attacks about the IRS’ targeting of conservative groups, the postponement of a major part of Obamacare and the Justice Department’s spying on journalists.”