IF 2012 is really the end of the road for President Obama, it is possible to see how historians might look favorably on his term. The president has already accomplished a great deal. His health care reform legislation promises to expand health insurance to millions of people and correct a number of flaws in our current system. His economic stimulus helped to stave off a second Depression and preserve the auto industry, while his financial regulations are meant to curb some of the abuses that led to the financial collapse of 2008. He has used executive power to strengthen some environmental regulations, while on foreign policy the killing of Osama bin Laden constituted an important step in the war on terrorism. Most recently, the role of the United States in the collapse of the rule of Muammar el-Qaddafi in Libya marks another victory in the struggle against dictatorships.

But passing a lot of bills and achieving military victories is not enough. Making them stick is the trick. As the political scientist Eric M. Patashnik of the University of Virginia has shown in his revealing book, “Reforms at Risk,” the fate of policy reforms is heavily dependent on what happens after laws pass. This is especially true for one-term presidents, who usually fail to build political coalitions that can survive longer than they can. President Obama must amass some political capital to protect these programs, or he risks losing everything for himself and for his party. He can’t govern based on the assumption that he will have more time to repair things.