Even though you live abroad full time and do not have a state of residence, you can still vote in Federal elections.
Most U.S. citizens 18 years or older who reside outside the United States are eligible to vote absentee for federal office candidates in U.S. primary and general elections. In addition, some states allow overseas citizens to vote for state and local office candidates and referendums. For information about your state, see the Voting Assistance Guide.
In some states, U.S. citizens who are 18 years or older and were born abroad but who have never resided in the United States are eligible to vote absentee. Direct your questions about eligibility to local election officials.
To learn more go to https://travel.state.gov/content/travel/en/international-travel/while-abroad/voting.html Since you are paying for it as a US taxpayer (though living abroad) you might as well take part in directing the way your US taxes are used. If you need help with your US taxes or estate planning, EMAIL US.