President Obama claimed repeatedly and recently that, under his health care reform, people could keep their health insurance plans if they liked them. As everyone knows by now, and should have known when the claim was first made, it is a load of nonsense. The fact is that millions of people will lose plans that they were perfectly happy with. It turns out that the Obama administration was aware of this fact years ago, but that the president continued to make the false claim anyway. Greg Mankiw has a rundown of the three scenarios under which this could have happened. As Mankiw says, "(n)one of them reflects particulary well on what has been going on in the White House."
The first possiblity is that the president and his staff didn't have any idea how their policy would actually work (incompetence all around). The second possibility is that the staff knew but let the president make false claims to the public (the president was incompetent and his staff were liars). The third possibility is that the president and his staff knew all along (they were all liars).