Matthew Yglesias (or, in Atrios lingo, "Big Media Matt") explains in The American Prospect why it really is important that the President of the United States be bright, engaged, and curious. You may have seen this article linked elsewhere, but you really do need to read it. The whole thing. Here's just one excerpt:

North Korean President Kim Jong-Il concluded that because Bush clearly meant to invade Iraq, had broken off negotiations with his regime, and was now lumping the two together as “evil,” he might soon find himself targeted. The result - a result that even a moderately engaged chief executive would have foreseen - was a North Korean rush to acquire nuclear weapons that could deter U.S. invasion before it was too late. By October 2002, the State Department sent officials to Pyongyang to confront the regime with evidence that it had been acquiring centrifuges needed to make weapons-grade uranium. Instead of offering the expected denials, North Korean officials conceded that, yes, they had done just that. After some trans-Pacific name-calling, Pyongyang let the other shoe drop: Not only was it processing uranium (which could take years to be successful), it was also kicking out the weapons inspectors who, under the Agreed Framework, were safeguarding North Korean plutonium rods that could be turned into nuclear fuel within months.

The time had come for the president to do something about the situation. So he did exactly what we were assured during the 2000 campaign he would do: He asked his advisers. The problem was, they didn’t agree. Some were hawks and others more dovish, so Bush couldn’t make up his mind. As Fred Kaplan wrote in The Washington Monthly, Bush “neither threatened war not pursued diplomacy.” Eighteen months later, with U.S. forces pinned down in Iraq and North Korea allegedly possessing several nuclear weapons, military options had to be taken off the table, and even administration hawks agreed that they had to pursue talks. Unfortunately, when you refuse to negotiate until you have no sticks left, it’s hard to get a good deal, and the United States now may be unable to secure a non-nuclear North Korea. And if we do get what we want, we will surely need to give up far more than we would have had we just negotiated in the first place.

Even better:

The issue is not “cleverness” - some kind of parlor trick or showy mastery of trivia -- but a basic ability to make sense of a complicated, fast-changing world and decide how to confront it. Any leader will depend on the work of his subordinates, but counting on advisers to do the president’s heavy lifting for him simply will not do. Unless the chief executive can understand what people are telling him and follow the complicated arguments they may need to make, he will find himself paralyzed at every point of disagreement, or he will adopt the views of the slickest salesman rather than the one who’s gotten things right.

Anyone who doesn't read this piece objectively hates America.