It is not necessary to go abroad to make something useful for the world.
As you live in a democracy, you can encourage the people you voted for to change some politics that the USA have and that are the source of a lot of pain in the poor countries.
The first things that come to my mind are the number of international treaties that the USA have not signed
1. the Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW
2. the Convention on the Rights of Children (CRC
). All countries except for the United States and Somalia have ratified it.
3. the Comprehensive Nuclear Test Ban Treaty
4. the ban
on antipersonnel landmines
(the Ottawa Treaty)
5. the Kyoto Protocol
6. the Law of the Sea Treaty
All those treaties, if signed and applied, can make the world a better place for poor citizens of poor countries.
There are also a number of treaties that the US has stripped to sign them
NOTE : Don't get me wrong, I am not your basic anti-US socialist european. In the numerous talks I had with people after the 11th september, I was always blaming those who said "It's their fault ! Good for them". I was (am) also defending the action against the taliban (except for the use of some nasty bombs).
But, being a supporter of the US must not hide that it's a BIG SHAME to have not signed, ratified and applied those treaties at least !
PS : sorry if some info is outdated, do not hesitate to notify me.