Because she doesn’t seem to have the curiosity that America needs for a President, especially when it comes to the foreign policy matters.

James Joyner expands that lead…

Bill’s right that it’s inconceivable that she got elected and re-elected to so many offices over the years, culminating with a state governorship, by being an airhead….I saw little evidence, though, that she’s very interested in foreign policy or most issues of American domestic policy. That doesn’t make her a bad person — she’s in the same boat as most Americans on that score — but it made her a bad choice for the vice presidency.

This is what Palinophiles — and, to be fair, some Palinophobes too — don’t seem to get. Palin’s problem isn’t that she’s a social conservative, or that she’s an airhead, or that she’s inexperienced. Her big problem is that prior to August 29, 2008, she quite plainly didn’t have the slightest interest in national or international policy issues of any sort. And no matter how much prepping she gets over the next four years, no matter how much better she gets at dealing with the press, no matter how much she does or doesn’t smooth off the rough edges of her social views, conservatives have to ask themselves this question: do we really want our standard bearer to be someone who didn’t become seriously interested in either domestic policy or foreign affairs until the age of 44? What does that say about how seriously we ourselves take this stuff?

I’m still stunned that we actually could have elected this person. It’s not that she’s a bad person. Far from it. Alaskans love her and it’s clear she’s a wonderful mom. But the President? There’s no way she should ever come anywhere close to holding that office. Because I agree with Joyner’s overarching sentiment that if you’re 44 and you’re not a student of history and current domestic and foreign affairs, it’s too late for you.

Politics Palin Doesn’t Have It In Her