和訳お願いします！
If you're an American and you're not having fun, it just might be your own fault. Our long national expedition is entering its 238th year, and from the start, it was clear that this would be a bracing place to live. There would be plenty of food, plenty of land, plenty of minerals in the mountains and timber in the wilderness. You might have to work hard, but you'd have a grand time doing it.
That promise, for the most part, has been kept. There would be land rushes and gold rushes and wagon trains and riverboats and cities built hard against cities until there was no place to build but up, so we went in that direction too. We created outrageous things just because we could--the Hoover Dam, the Golden Gate Bridge, the Empire State Building, which started to rise the year after the stock market crashed, because what better way to respond to a global economic crisis than to build the world's tallest skyscraper? We got to the moon 40 years later and, true to our hot-rodding spirit, soon contrived to get a car up there as well. The tire tracks left on the lunar surface (tracks that are still there) are the real American graffiti.
