It appears that the US has certified Bolivia's fight against illicit drugs. In doing so, US aid to Bolivia will not be interrupted. Laying aside the monumental failure and waste of time that the US "war on drugs" has become, the Bush administration's decision to certify Bolivia is smart politics (and another example of why Assistant Secretary Tom Shannon is the right man at the right time). First, Bolivia is teetering on the edge of chaos and the last thing the US needs to do is insert itself in this combustible mix. A de-certification could have created a rallying cry for Evo's supporters and aggrieved nationalists and, undoubtedly, put some wind back in Evo's sails (at a time when, it appears, he is backing into a corner and could possibly make some concessions to the opposition). No need to push Bolivia into failed state status.
Also, a de-certification would have aided Chavez's cause more than ours. I know many proud Bolivians and Evo supporters like to pretend otherwise, but Evo is Chavez's puppet. There is very little free agency going on here. The US recognizes this and, in its policy, it *should* seek to drive a wedge between the two knuckleheads. The drug certification process does this by de-certifying Venezuela, but certifying Bolivia. A Bolivian de-certification would have validated, in Evo's and his supporters' eyes, the relationship with Chavez. It would have strengthened the Venezuela-Bolivia relationship and further weakened the US-Bolivia relationship.