Surely, you jest.
Five hundred years ago, the most powerful entities in the world were the Ming Empire in China and the Ottoman Empire in modern day Turkey. If anyone had said that the most powerful mercantile, agricultural and creative industrial powers in the future, ones creating untold wealth for millions of people, would originate in what was then a rustic Europe and a wilderness in North America, they would have been deemed insane.
I will repeat for you: we have the technology to mine near Earth asteroids and the Moon. We have the time to go about it slowly and carefully, step by step, establishing manufacture in space exploiting the zero gravity vacuum of space capable of creating unique metals due to its lack of gravity.
This opens up the possibility of innovative and new products resulting from materials that cannot be created on Earth.
We have rail guns mounted on navy ships that launch large projectiles; there is no reason such devices cannot be used in space, utilizing solar energy, to launch space vehicles.
We are only limited by our lack of imagination and fear of risk. It took courage to settle the North American wilderness, and there were mercantile companies that financed many such endeavors.
If the United States doesn't take the next step, some other nation will do so, and it will be to our disadvantage.