IF there's a primary election in a specific state, the state laws or court rulings apply. If there's a caucus or no popular selection at all, that's entirely up to the party.

that is sure to gain some faithful followers of 'H', indeed.

Like they knocked Obama off the ballot in 2008?

See, e.g., Smith v Allwright (1944)

We're a stubborn bunch.

In Texas, you do not register as a member of a party but once you vote in one party's primary, then you can not vote in the other party's primary for the remainder of that election cycle. Neither Papa Bush, W nor Carnival Cruz' voter registration will show them as being registered as a republican. I guess that Papa Bush and W cheated when they ran in the NH primary

If they did keep Sanders off the ballot they would disenfranchise people from voting for him as a candidate. Although voters could write in Sanders, those ballots would be subject to more scrutiny than a ballot with his name on it including the possibility of being challenged.

Bill Gardner has been Secretary of State for nearly 40 years. In NH the Secretary of State is elected by the legislature which, until the last 10 years or so, was in the iron grip of the Republican Party.
Before that, he was a state rep - one of the handful of state reps making up the Democratic caucus back then. It was a mountainous challenge to fill out town and city ballots with Democratic candidates for state rep. Gardner was in charge of recruiting Democratic candidates and recruited me to run for state rep in 1976.
As an aside, I got whipped in that race. I think Jimmy Carter got about 37 percent, which was about the norm for a Democrat in NH then.
My overly delayed point is that he is completely fair and plays everything straight down the middle when it comes to his official duties. It isn't in his makeup to stick it to anyone.

State laws aside, my view is that it is not to much to ask that someone running for a party's nomination be a member of the party.
BTW, I don't know who I'll end up supporting in the primary, but Bernie Sanders is closer to my political philosophy than anyone I have voted for in 10 presidential primaries.

Obviously, one does not have to be registered with either party to run in NH. Howard Dean, the Bushes, and on and on. What part of VERMONT HAS NO REGISTRATION BY PARTY is so difficult to understand. 20 other states don't either. The DNC has welcomed him to the race, so who the fuck is Gardener to try and exclude him on a patently bullshit premise? He said you have to be a REGISTERED Democrat or Republican to run in NH. In that case, your revered SoS has been doing a piss poor job over the last 40 years of keeping candidates who are not registered, off the ballot.

I don't remember saying anything about revering him, but if that is how it sounded, I made some poor word choices, I guess.

By the way, YOU DON'T NEED TO YELL! I CAN HEAR YOU!

This is going to be a fun primary if there is going to be this sort of dialogue.

There is no party registration in Illinois.