Well them helping us in the American Revolution is a tad larger than helping us in WW1 or WW2, but I'll give it to you.

Countries do things when it's in their best interest. Right now, G W Bush thinks it's in our country's best interest to take out Hussein. It's definitely in France's best interest to not fight Iraq. France has practically no oil on their land. They mainly depend on nuclear power, which while it is better in some respects, it's more dangerous. The oil that they do get is almost 100% from Iraq. If they help fight Iraq, they lose all their oil, and would have to depend even more on nuclear power.

There's no concept of "paying back" when you help other countries, except if you give them money.

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