What are you talking about?

http://www.uscitizenship.info/uscitizenship-dual-citizen.htm

The concept of dual citizenship means that a person is a citizen of two countries at the same time. Dual nationality laws and policies depend on each country. The U.S. Government recognizes that dual citizenship exists, but does not endorse it as a matter of policy because of the problems that it may cause. Dual citizens owe allegiance to both the United States and the foreign country. They are required to obey the laws of both countries. Either country has the right to enforce its laws, particularly if the person later travels there. There may be a conflict with the U.S. laws, which may cause problems for the dual citizen. Additionally, dual citizenship may limit the United States Government's efforts to assist United States citizens abroad.

__________________________________________________

It's not endorsed but it's ok. As long as you use your US passport when you enter USA, The US government doesn't care if you have passports from other countries.