You can still vote in U.S. elections if you live in Panama, but keep in mind that the US Embassy is not a polling place. Therefore you cannot vote on election day, you have to act in advance. First of all, request an absentee ballot from your local election officials back in the U.S. Some states accept e-mail, but most require that your ballot is received physically before the close of the polls. You have therefore the option of sending your ballot by courier (FedEx usually offers special rates prior to election day), or simply to drop it off at the Embassy in a US postage paid envelope addressed to your local election officials. If you need assistance, the Embassy personnel is very helpful. Just make sure you don't wait until the last minute, and make your vote count!