So you think that something similar to the voter identification card on a national basis would serve as an alternative.
One example that was talked about concerned the Australian method. The Australian method, of course, is that if you don't have any ID, you vote but you provide an oath in writing, and it is sealed with the ballot and checked at a later date. I personally like that, because then people are not discouraged once they're there, even though they have no ID. Their vote may be discounted because they don't match up, but at least they're not told to go home and come back later.