The costs to U.S. foreign policy, including relations with major trading partners and the World Trade Organization, almost always outweigh the potential benefits of coercing friends. This is the lesson of U.S. secondary sanctions imposed against Europe and Canada over their refusal to support broad U.S. sanctions against Cuba, Iran and Libya. Tailor sanctions narrowly. A focused response helps avoid jeopardizing other interests and an entire bilateral relationship over one area of disagreement. Such a response also does less harm to innocent people and makes it easier to garner multinational support.
Sanctions designed to stem the proliferation of weapons of mass destruction are a prime example.
Where there are transgressions, the U.S. should direct any sanction against the foreign firms involved. If the government is to blame, Washington should cut off technological cooperation or trade in the relevant technologies. Political sanctions should be used sparingly if at all. U.S. officials should resist the temptation to break diplomatic relations or cancel high-level meetings. Such interactions provide opportunities for U.S. officials to make their case.