They can give you the specifics for your state/county caucus registration rules.

I've seen parents bring kids to attend a caucus, to see how this is done. And... based on 2008 anyone can just come and register on the spot. By the time someone, anyone? checks the list and find many who could not vote - not living in the district - the results were submitted and tabulated.

To participate in the caucus and/or cast a preference ballot you only need to be eligible to vote on election day. The only requirement is that you sign in or you will not be given a preference ballot.

The parties set the rules for their caucuses (not the state) and at my convener's training we were told to not ask for IDs if there is any doubt but to take people at their word (we've never asked for IDs). It's not impossible that someone would challenge him but I've been attending caucuses since 1972 and have never seen that happen. Besides, you'd be there to vouch that he's currently living in the precinct in the unlikely event that someone did this.

BTW 16 and 17 year olds (referring now to 17 year olds who will not be 18 by election day) may attend the caucus but they cannot be elected as delegates to the next level nor can they participate in the preference ballot.

He is getting his MN ID today and will probably bring home a voter registration card