Would it stop Democrats from voting twice? (or twenty times...)
Given the certainty that, as soon as somebody proposes that the "ID Card" be required at the polls, 1)the Democrats will scream bloody murder and 2)the Republicans will bend over like the 98-pound weakling in a SuperMax cell block, why even bother with the proposal anyway?
It would make it easier to do so. Only the card need be checked, not the voter. The need only be a correspondence between the number of cards and the number of votes, not between the number of voters and the number of votes. The main difference would be that some people would feel safer.