From Karl Rove's April 29 Wall Street Journal column:

Before his health-care bill passed, Mr. Obama sent a tough letter to health-insurance CEOs and then castigated them 22 times in a follow-up prime-time televised speech. This is behavior worthy of a Third World dictator-not the head of a vibrant democracy.

[...]

But it is the president's intimidation that is most troubling. Mr. Obama has the disturbing tendency to question the motives of those who disagree with him, often making them the objects of ad hominem attacks. His motives, on the other hand, are pure.

Mr. Obama often makes it seem illegitimate to challenge his views, and he isn't content to argue issues on the merits. Instead, he wants to make opponents into pariahs. And it's not just business executives who are on the receiving end. We've also seen this pattern with the administration's attacks on the tea party movement and those who attended town-hall meetings last summer on health care.

This is a bad habit-and a dangerous one. The presidency is a very powerful office, and presidents need to be careful not to use it to silence dissenting voices.