Last week, 30 Columbia University graduate students and I spent two long days in meetings with senior officials at the State Department and National Security Council; on Capitol Hill; and with experienced Washington journalists, economists, consultants and lobbyists. Most of us probably expected to come away wondering whether, in its overhaul of American foreign policy, the Obama administration has found a winning strategy for dealing with tough problems such as Iran or North Korea. By the end my conclusion was different. What the president and his team really need is a strategy for dealing with Congress.

Our field trip came three days after President Obama announced his refashioning of Cuba policy. Not surprisingly, my students asked why the changes were so limited,...