After George W. Bush defeated Al Gore at the ballot box and in a rare show of fortitude for a Republican, didn't stand by haplessly wringing his hands when Gore tried to lawyer his way into the White House, liberals were outraged. Sure, Gore had never been ahead at any point, but OBVIOUSLY voter fraud had cost Democrats the election. Afterwards, Democrats DEMANDED that we do more to insure the integrity of our elections. Republicans agreed and for a while, we finally had an issue where there was genuine bipartisan agreement. Then came the 2004 elections and many of the same liberals who had requested better, more accurate voting machines claimed the very machines they wanted were being used for fraud because they didn't get the result they wanted. That marked the end of the Left's interest in stopping fraud at the ballot box.
On the other hand, Republicans have continued to try to make our elections honest and fair. Towards that end, one of the measures the GOP is pushing for is voter identification. If you need a picture ID to get on a plane, cash a check, buy alcohol, rent a car, get a marriage license, or to get into the Democratic National Convention, then asking for a photo ID to vote is a no-brainer. However, Democrats believe that they benefit from voter fraud; so they oppose any sort of attempt to verify that voters are who they say they are.
They can't admit that; so they use two excuses. The first is their patronizing and insulting claim that black Americans are so uniquely stupid and incompetent that you can't expect them to get a photo ID like white people do. It's amazing that in 2012, a major political party would make such a racist argument, but the Democrats do. Their other claim is that voter fraud is so exceedingly rare, so unlikely, such an impossibility that there's no need for any voter identification. According to the Democrats, we can afford to assume that everyone will be honest on Election Day. So, there's no need to take any basic precautions or take any steps to prevent fraud because it just doesn't happen.