Keeping immigration on the back-burner helps avoid a recess filled with angry town-hall meetings reminiscent of the heated August 2009 protests where the backlash against health care reform coalesced. Doing nothing also starves Democrats of a target, Republicans argue. But for Boehner, who by all accounts wants to see some kind of immigration reform pass, that raised serious strategic problems. First, passing tougher enforcement measures before August would take all the momentum away from other more divisive measures, such as giving “Dreamers,” the children brought to the United States illegally, a legal option for staying in the country. While House...