I'd heard some info about this in the last few days, but Matthew Breitbart's Big Peace site and the Washington Times have a pretty good roundup of what's going on.
Short version, the government got told they have to make sure deployed troops can vote. the Obama administration, knowing that troops will vote against democrats, has seen fit to pass on actually enforcing the rules that will make it so troops are guaranteed their rights to vote even when deployed.
Instead, as is noted in the story, the Obama administration is more interested in restoring voting rights for felons - as he expects them to vote for him.
Transparent pandering to whoever will vote him and his leftist cronies into power in perpetuety.
It's not who votes that counts, it's who counts the votes.
- Josef Stalin