Hispanic voters and Democrats

Doug Mataconis at Outside the Beltway has at least an initial answer to a question I posed not long ago about whether the Obama administration would alienate Hispanic voters by putting up immigration bills that were almost certain to fail.  Here is the graph from Gallup:

This is too short a time frame to come to firm conclusions, since there were dips before (i.e. April 2010) that then saw a rebound.  But how many policy failures will it take for those numbers to stay low?