Intelligence and catastrophic policy positions are not mutually exclusive. The real question is whether he's wise enough to know better.
On several occasions, I've run across election observers who posit that Mitt Romney is too smart to believe various hawkish statements he makes about foreign policy on the campaign trail. An insightful retort has just been articulated by Daniel Larison, whose arguments warrant wider attention. He writes:
It would be encouraging to think that the government wouldn't make grave mistakes if it were staffed by sufficiently intelligent people, but sometimes the government pursues disastrous, unrealistic policies because some reasonably intelligent people believe that they have found a "solution" to a major problem, but the "solution" is poorly-designed or ill-conceived. The point here isn't that intelligence is unimportant, but that having intelligent people at the helm doesn't prevent major policy blunders and may sometimes lead to policies that are excessively ambitious and doomed to fail.
As much as I criticize its record, the Bush administration didn't lack for smart people. Even Bush did not make the foreign policy mistakes he did because of a lack of intelligence as such, but because he didn't know as much as he needed to do his job well and because he accepted certain extremely flawed and ideological assumptions about the world and the ability of the U.S. to shape other parts of the world. Intelligence doesn't guarantee wisdom or prudence, so I wouldn't assume that someone as smart as Romney is supposed to be doesn't seriously hold the foreign policy views he has publicly stated. If Romney has no foreign policy experience and hasn't given much thought to these issues, he could be very smart and still be very ignorant.
There's a broader insight to take from all this: America would do well to gauge and compare the smartness of candidates less frequently, and to focus more on their prudence, wisdom, integrity, ability to avoid hubris, and commitment to being informed rather than using ideology as a shortcut.
Chris Hayes made this larger point well in his book Twilight of the Elites:
While smartness is necessary for competent elites, it is far from sufficient: wisdom, judgment, empathy, and ethical rigor are all as important, even if those traits are far less valued .... Extreme intelligence without the other qualities I mentioned above can be extremely destructive, But empathy does not impress the same way smartness does. Smartness dazzles and mesmerizes. More importantly, it intimidates. When a group of powerful people get together to make a group decision, conflict and argumentation ensue, and more often than not the decision that merges is that which is articulated most forcefully by those parties perceived to be the "smartest."
It is under these conditions that destructive intelligence flourishes. Behind many of the Bush administration's most disastrous and destructive decisions was one man: David Addington, counsel and then chief of staff to Dick Cheney ... a figure who used his dazzling recall, razor-sharp logical ability, and copious knowledge to implacably push the administration policy in a rogue direction. because he knew the law so well, because he possessed such a gifted mind, he was able to make legal arguments that, executed by anyone else, would have been regarded as insane ... This dynamic, in which the smart, sneering, self-assured hawk steamrolls his ideological opponents, should be well familiar to anyone who watched the run-up to the Iraq War. One of the great mysteries of the last decade is how so many smart people could end up endorsing an idea as stupidly destructive as the Bush Administration's war on Iraq. There are a multitude of reasons, of course, but postwar reflections by intellectuals reveal how important a role the Cult of Smartness played in getting them to go along. Many smart writers came to be convinced of the merits of war because it seemed to them that the war's proponents were "smarter" than its opponents.
This same lesson ought to have been learned way back when The Best and the Brightest was published. But we persist in trying to gauge the smartness of candidates far more often than their wisdom. Of course, it is possible that very few wise people ever run for president in the first place.