I hear that allegation frequently, but nobody ever explains why. You can't get an absentee ballot unless you are registered.
If you require sufficient ID for registration, absentee ballots should not be a problem.
There is evidence that groups such as ACORN turned in voter registration forms with fake names on them. Then the absentee ballots get mailed out, to a fake person, and the ACORN or other people fill it out.
True you can’t get an absentee ballot unless registered, however, it’s possible in many places to be registered without ever having to physically show up at an office. They mail forms in, get the names on the voter rolls, then absentee ballots are mailed out to fictitious people. ACORN type people then make sure the ballots are voting for the “correct” people.
There are many methods and they keep inventing new scams.
See my short booklet on vote fraud and how to prevent it as well as some of my more recent experiences:
http://www.freerepublic.com/focus/f-news/1991953/posts
http://www.freerepublic.com/focus/f-news/2378786/posts
It will not matter if the states pass a voter ID law unless the Precinct has at least one Republican to make sure the dims follow the law.
Volunteer!