Morales moves against Yanquis

...from Brazil:

Petrobras, the biggest investor, with over $1 billion invested in Bolivia, criticized the government's "unilateral attitude" and said it would take whatever steps necessary to "protect the rights of the company" and guarantee Brazil's supply of gas, half of which comes from Bolivia.

(Bolivia nationalises oil and gas sector) But how much leverage do the Brazilians have? They need the gas, and the market is tight.