Citizenship comes with only drawbacks these days.
You can be a temporary (think H1s, student visas, etc) resident, a provisional permanent resident (essentially it's what lets you be a resident for the extended period it takes to approve a green card in which your original work permit might expire), or a permanent resident (i.e. a green card), and in all those cases you pay at minimum the same taxes as citizens.
On the other hand, if you just walk across the border, you qualify for all of the benefits, and even now get to vote just like citizens, but there are no obligations at all. You even qualify for free housing, free healthcare, free internet and cellphone service, and free food, just for showing up without papers.
