From Reuters:
Brazil may challenge the legality of a "Buy American" clause in the recently approved U.S. economic stimulus package at the World Trade Organization, Brazilian Foreign Minister Celso Amorim said on Monday.
"It's a complex legal analysis, but we're doing it," Amorim said.
...
Amorim said he thought Brazil could challenge the "Buy American" clause at the WTO, despite not being a signatory to an international agreement on government procurement.
I'm curious to hear their legal theory.