Again, there are all types of government assistance. One famous American received a $77,000 tax credit last year for upkeep and dance lessons for his horse. Lots of Americans don’t make that kind of money, let alone have the government let them keep it.
Perhaps a better approach would be to have a basic intelligence/ general knowledge test. If you can’t find Canada on a map, you can’t vote.
If you think Romney killed Osama bin Ladin (as one poll found 5% of its responders believe), you can’t vote.
More valuable than a drug test?