States can quickly get new supplies and does not have troops away from the homeland. Next, Canada would be invaded. Now, the United States has control of an entire continent and can efficiently manage the previous borders.
After the United States has successfully conquered North America, there needs to be a boycott of Chinese goods. The United States is the number one recipient of Chinese goods. By boycotting the goods and services, the U.S. can cause a global economic crisis. The stock market of many nations would crash, just as China's would. This makes nations that are over seas easier to conquer as they are economically unstable. The U.S. will be tremendously affected by the crash of the Chinese stock market. To make up for their loss, the U.S. will need to create thousands of new jobs to heal the wound left by China's absence.
As the worlds economy falters, the United States can acquire crumbling nations with the promise to restore economic balance. Countries in Central and South America will provide a large territory, millions of new civilians, and an ample amount of natural resource. They may go quietly, as their economy has been ruined by China's economic disaster. However, these nations may also choose to initiate nuclear or chemical warfare. Chaos would pursuer this decision as the United States may choose to strike back. Many nations over seas have nuclear war heads. Russia, Germany, and China have the most war heads in the world next to the United States. The decision to move thousands of troops and supplies across the ocean is a very large obstacle. These nations are thousands of miles away and could strike at any moment.
Overall, the decision to become a true empire would be extremely costly. Thousands would die in the countless wars against different countries. Creating an economic crisis may be the best decision to weaken other nations, however, there is no guarantee that the U.S. would not vaulter under this decision. The possibility of nuclear warfare would also loom over every countries head as the U.S. continued to conquer other nations. Therefore, the decision to become a true empire would prove to be a costly and possibly disastrous decision.