Dual citizenship.....?

yes Slovenia does allow dual citizenship, so do the US among many other countries;

but not if you were naturalized in Slovenia,

so,yes you may have US citizenship:http://en.wikipedia.org/wiki/Slovenian_nationality...

NO - sorry.

Dual nationality is normally prohibited with considerable exceptional permission

http://www.geocities.com/jusjih/dncdp.html

scroll down to slovenia

The No/Yes definition is at the top.

From the wikipedia link above

Dual citizenship is permitted in Slovenia, with the exception that those acquiring Slovenian citizenship by naturalisation are normally required to renounce any foreign citizenship they hold.

You were born in slovenia so you might be ok - but you might want to contact a slovenian embassy or consulate and ask.

The US does not encourage dual citizenship, but has no specific law prohibiting it. The U.S. Government recognizes that dual nationality exists but does not encourage it as a matter of policy because of the problems it may cause. Claims of other countries on dual national U.S. citizens may conflict with U.S. law, and dual nationality may limit U.S. Government efforts to assist citizens abroad. The country where a dual national is located generally has a stronger claim to that person's allegiance.

Slovenia recognizes dual citizenship for its' birth citizens, but requires naturalized citizens to renounce their former citizenship.

Mexican Americans and American Mexicans have dual citizenship, because we are neighbors, partners and allies.