Elderly Politicians

I just read this Guardian article, which talks about how there is mounting pressure for Silvio Berlusconi to step down before the next election. The main reason? He is too old, even if he did have a facelift.

The strange thing is that Berlusconi is only 69! It's interesting that here in the U.S. there is really no age limit on politicians. When Reagan ran, there was some fuss about his age, but it obviously didn't stop him from two terms in office. And people like Senator Thurmond are allowed to totter around the Senate well past the point of senility. I wonder why the difference between here and Europe. I have no problem with older politicians, per se, but it seems like in the United States some people value it as a positive quality in and of itself.