It's really more the heightened power of the minority caucus of the Senate which has recently radically expanded what were previously relatively minor veto points in the path of legislation[1]. It's not quite a liberum veto [2] yet but it has some of the pathologies.

[1] http://upload.wikimedia.org/wikipedia/commons/thumb/7/79/Clo...

[2] http://en.wikipedia.org/wiki/Liberum_veto