BANGKOK — Is voting in your pajamas worth the security risk of doing it through email?

BANGKOK — There is no variety of American voter quite so unreliable as expatriates. They poll to the polls far less frequently than even teenagers and high-school dropouts. When it comes to campaign contributions, they donate less than 1 percent of the total haul. Compounding their low turnout rate — a scant 7 percent in the 2008 US presidential race, according to the non-partisan Overseas Vote Foundation — is the mystery surrounding their voting habits.