You also have issues of deanonymization if you only get a couple of ballots in via one method. In Maryland, for example, they're supposed to encourage at least 100 random people to use the accessible ballot marker per precinct for this reason.
It's not reasonable to tell people "too bad," fly back to the US as much as 3 times per year. They pay taxes and are subject to US law even though they're overseas, so they get to vote.
Ballot management becomes error prone. My county alone has 25 ballots due to the different combinations of state house, senate, Federal house, municipalities, and _all_ the special districts. (4 members to the board of directors of the Anytown West Memorial District, a.k.a. cemetery, because they had a property tax assessment when they built the thing in 1950)
I offered nothing of the kind, except as to civilians residing abroad, and even then, I don't think there should be any obligation to provide online voting -- having to travel to a consulate is not too unreasonable.
> It's not reasonable to tell people "too bad," fly back to the US as much as 3 times per year. They pay taxes and are subject to US law even though they're overseas, so they get to vote.
Vote... where? In what state, in what county, in what precinct? The correct answer is that they should not have to pay income taxes while residing abroad, but also not get to vote while residing abroad.
For military the situation is simpler even if the personnel have no US-side residence: use the state/county/precinct of last residence. The same can apply to civilians, but I'd rather let them not pay state and federal income taxes while residing abroad.
> Ballot management becomes error prone. My county alone has 25 ballots due to the different combinations of state house, senate, Federal house, municipalities, and _all_ the special districts. (4 members to the board of directors of the Anytown West Memorial District, a.k.a. cemetery, because they had a property tax assessment when they built the thing in 1950)
That's a small county :)