Bill Clinton left his first Secretary of Defense Les Aspin, who was not well suited for the job, twisting in the wind while he pondered his fate. When a military operation in Mogadishu, Somalia, in 1993, resulted in 18 U.S. soldiers killed and 73 wounded, a sacrificial lamb was needed and Aspin was the obvious choice. Trouble is Clinton couldn’t bear to do it, so he delegated the task to National Security Adviser Tony Lake, who was a friend of Aspin’s. But Aspin demanded a face-to-face meeting with Clinton and talked the president out of canning him — at least temporarily.

Sometimes presidents resort to extreme measures to remove a few bad apples from the Cabinet. Both Richard Nixon in 1973 and Jimmy Carter in 1979 demanded letters of resignation from their entire Cabinets. This allowed both to avoid going eyeball-to-eyeball with those members they really didn’t want back.

So why is it so tough for the “most powerful man in the world” to boot out subordinates? Some underlings have stood by the president through the long trek to the White House. Others are supported by important constituencies. But perhaps the best explanation is that they’re politicians. And politicians, as columnist Elizabeth Drew once wrote, just want to be loved by everyone. Obama is a politician. Perhaps that’s why so few prominent heads have rolled for the Obamacare breakdowns.