New Delhi, Aug. 5 -- WASHINGTON - Maria Luiza Ribeiro Viotti arrived in Washington with a mandate to manage one of Latin America's most consequential diplomatic relationships. On Tuesday, the Trump administration made that mandate considerably harder to fulfill, revoking her United States visa in what the State Department described as a reciprocal response to Brasilia's decision to block two senior American officials from entering the country ahead of October's presidential election.

The move stops short of declaring Viotti persona non grata, the formal expulsion mechanism that would end her mission and force a rupture in Brazil's diplomatic presence in Washington. But it lands with unmistakable force. A State Department spokesperson con...