This is an issue that everyone, conservatives, liberals and fauxgressive Obama supporters alike should be concerned about.
Any kind of election fraud, including dubious voter registration, undermines the integrity of our political system and the legitimacy of our leaders. For eight years the left has been pointing to Florida in the 2000 election as proof that George W. Bush was not legitimately elected. Now many of those same lefties want to recreate that same argument to be used against Obama if he wins. And if you think the GOP will emulate the do-nothing Democrats and ignore the issue you are high on hopium.
Remember when progressives had principles? Liberals still have them.