Liberals are up in arms this afternoon because acting – acting – head of the Federal Housing Finance Agency has blocked the latest Obama Administration attempt to do something about the housing market.

I’ll let you go to any of those links for more on the substance, but the bigger story is what David Dayen tweeted: “There has been a replacement nominee for FHFA Director for about 2 months in the 3 years that Ed DeMarco has held the acting director spot.”

I’ve said it before: the failure to move aggressively to fill the executive branch with his appointees has been the biggest mistake Barack Obama has made during his four years in the White House.

And I’ll say again what I said earlier today about judicial nominations. Yes, Republican obstruction has been unprecedented – even more so on executive branch nominations than it’s been on judges. But that’s no excuse. It clearly hasn’t been a priority for the administration. Had it been, pretty much every single nomination could have gone through the Senate in 2009 and 2010, when they had plenty of votes, and there’s a pretty good chance they could have filled vacancies as they came along even after more Republicans were in the Senate after the 2010 elections. And that’s not all: I also think liberal interest groups and activists deserve some of the blame, since many of them also ignored or placed a low priority on the personnel problem.

Legislative leadership is important in the presidency, but fighting to get policies adapted and implemented within the executive branch is an enormously important part of the job. Even with a good group of presidential appointments in place, it’s still going to be a battle in many cases, and the permanent bureaucracy can be extremely good at resisting change (as can Congress and outside groups working through the bureaucracy). With holdovers and vacancies? Good luck. There’s simply no excuse for this unforced error.