One can register and vote at the same time, on the day of the election, without a photo ID. One need only provide proof of a valid address in the district you are are voting in (usually a utility bill) or bring someone to vouch for you being a resident of the district, who is a registered voter.
In other words, MN has voting laws which if applied in Zimbabwe or other Third World states would be universally derided as unfair and an invitation to corruption and ballot-stuffing.
Let's think of what engineers call the "abuse cases". Let's suppose there is a pool of people who'd happily countersign votes from people they knew weren't allowed to vote, as a first condition for corruption. This corrupt state's police force or military will do nicely. Now, what else do we need? Well, can you easily fake a utility bill? Or if utility bills are unfakeable, can you get someone within the utility company to print you off a thousand? Either way, job done.
Then the check against the Secretary of State's records. Well, which records are those? and what are they checking for? If it's just for duplicates, I can print up a thousand utility bills for fictitious houses on Nowheresville Drive, Nosuchtown, MN and there ain't any way you'll spot it.
Let's remember that high voting figures don't necessarily mean that a high number of people went to the polls.
And let's suppose that everyone in MN is fundamentally honest, and they really *don't* have any problems yet. They've still done the electoral equivalent of leaving the front door ajar. Whether there actually is any abuse is immaterial to the fact that it's *open* to abuse.