After the American Revolution, why did other nations look to the United States as a model nation?

"The U.S has been necessary to retain their freedom" would be the appropriate response.

Explanation:

Only after the American Civil war, several states saw the U.S as a successful state seeing as how the U.S was interested in preserving its sovereignty. The Continental forces, commanded by Colonel George Washington, vanquished several British soldiers throughout the American revolution because that's how the U.S achieved its autonomy from either the foreign king.

They showed the country that integration could be successful.