What Is This Kyoto Treaty Thing?

Can somebody please explain to me what the big deal is with the Kyoto Treaty on global warming? One of the first things George Bush did was to come out against it. He did a trip to Europe in 2001 (before 9-11) and was roundly denounced for it. Afterwards, a funny thing happenned. The obvious question was posed . Why hadn't any of the other countries ratified it?

Before Bush there was Clinton. The treaty had come up for a vote in the US Senate. It was unanimously voted down. This always struck me as a significant fact. Every Democrat had voted NO on the treaty. AND no other nation had ratified it.

After the Bush European trip, where all those politicians had bashed Bush and America for the attention of all those voters back home, European ratification became an issue. So, they had a big meeting in Vienna (rather than just going ahead and ratifying it). There they added a little clause at the end of the treaty. "None of this is legaly binding." Then they ratified it.

This has always struck me as a significant addition. Since then the announcement by one nation or another that they will fail to meet their Kyoto targets has been a routine part of the news.

So, what's the big deal with this Kyoto Treaty thing?