Who is the real threat to the United States?

Who is the real threat to the United States? Neither Russia nor China are it, although they have the potential to be it. All other global representatives, such as terrorists, can do harm, but it would be minimal. The real eminent danger is the enemy from within. Who is that specifically? Mostly, those who wish to transform the United States into another country different from what the founding fathers established when the United States Constitution was adopted as the law of the land.