Presidential polls going down from the start of the presidency in the US?

A lot of people make a lot of noise about the polls of President Obama going down. However, a closer look on the tracker for polls from Gallup shows that most presidential polls go down. Nearly the only exception is that of Bill Clinton's that showed a steady rise all through his presidency. And this was despite the Monica Lewinsky scandal and the failed health care bill.

I'm intrigued about the fight between the Democrats and the Republicans. It seems to me that it is all about which is the American way of this century. Is Obama going to change Robert Kagan's Dangerous Nation into a nation that truly minds its own business and that speaks more softly? Or are the Republicans going to mow him down to a Carteresque existence. As Carter, he is intelligent, and that carries the risk of trying to solve problems by himself instead of leading with his political intelligence.

It is early to guess, but I feel President Obama is going to get his second term, somehow. The main reason is that America is going to be dependent on opinions in the world. The other view, that of Cheney, scares people in for example Europe. However, I remember from the election campaign that China is more Republican.