For those who responded to Eric Lichtblau’s earlier report by saying that the FEC was always gridlocked and dysfunctional, it’s just not true. It never had great enforcement powers, but there was much more cooperation on rulemaking, and much more agreement on enforcement matters. (Here’s some evidence from Michael Franz.)
In my view, we can trace origins of the new era of dysfunction to Don McGahn.
It is an ideological split, in the sense that Republican commissioners consistently vote for less regulation and Democrats for more, but it is partisan in the sense that Republicans tend to believe that deregulation works in their favor and Democrats believe it works against them. The two cannot be separated.