What kind of powers are given to the national government simply because the US is a sovereign nation?

The major powers belonging to a sovereign state refer to security and the economy. A central government needs to ability to be the sole issuer of money (both coins and bills) so 'cheaper' money does not debase it. A sovereign state also needs the ability to control it's own defense by being in sole command of it's armed forces. It also needs the ability to levy taxes in order to pay for the basic services its citizens require.