Katherine Kersten offers this Star Tribune column. She writes:

Some states with same-day registration try to blunt fraud with “provisional” voting. Under this arrangement, election officials set aside the ballots of voters whose eligibility is in question, and count those ballots only after verifying a voter’s eligibility. Not in Minnesota. Here we commingle all ballots. After the election, officials may discover that you voted illegally. But your vote has the same effect as any lawful voter’s.
Some would ask: Is there a real problem here? After all, it’s a felony to vote illegally. But Secretary of State Mary Kiffmeyer says that Minnesota’s unique combination of no photo ID requirement, same-day registration and vouching can make it difficult– sometimes impossible — to trace or catch lawbreakers.

Thanks to a reader for passing this link along.