Dony
the answer is Mexico
The southwest region of the United States borders Mexico.
Mexico.
Mexico
Texas borders just one country (besides the US), that's Mexico to the southwest.
Spain
mexico
Both Guatemala and Belize.
Ecuador borders southwest Colombia, and Panama borders northwest Colombia.
Ukraine
Southwest of Iraq is Saudi Arabia, which while it does border the Persian Gulf is NOT small. Kuwait is on Iraq's southeastern border and is a small country that borders the Persian Gulf.
Vietnam