1. The economy is in the dumps, but its not bankrupt. And no, our economic situation was not causes by Europe, though Europe certainly isn't helping.
2. US is definitely lagging behind in green energy, but we've been getting much more serious about it. The majority of people still clinging to the idea of no global warming are the oil companies and the people they've bought.
3. US didn't do it alone, though we certainly played a huge role. Without the US, Germany could turn all of its attention to the Soviets. Without the Soviets, Germany could turn all of its attention to the western front. It would be hard to argue either could have won without the other.
4. China's got its own problems to deal with. They're far from a perfect country as well. But I'd much rather be a citizen of the US as of now than China.