The Democratic governors are worried about how the party will fare in the November elections. The Washington Post has a gloomy interview with Governor Bredesen, D-TN. Many pundits are predicting large Democratic losses in the fall.
Democrat governors appear to be more closely linked to the public mood on illegal immigration. They see the national Dem leaders in Congress and the White House falling on their own swords over this issue, and taking the party down too. See this New York Times article for details. This Politico article has more.
It is smart politics to blame Washington before Washington blames you. However, in this case the blame appears to be well-placed.