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Secretary of State Hillary Clinton returned empty-handed from Brazil. Neither Foreign Minister Celso Amorim or President Luiz Inacio Lula da Silva were responsive to her arguments for supporting stronger sanctions against Iran.

This shouldn't have been a surprise. Brazil has long made clear its stance on the Iranian question: it wants proof that Iran is working not on mastering nuclear technologies, but on actually constructing a weapon. Barring some sort of Adlai Stevenson moment"”which the Obama administration has not been able to generate"”Brasilia is not eager to condemn what it sees as activities that any rising power should have the right to engage in.

But the ramifications go far beyond getting Brazil's support in the Security Council. Efforts to get a...