In Gmail a folder is a file you put a message in and a label is a tag you apply to a message. Folders are exclusive; a message can't be in more than one. You can toss on as many labels as you want.
Both help you sort messages but multiple labels can tell you so much more about a message's contents.
American political parties are folders. Republicans, Democrats, Libertarians, Green, Constitution, etc... Candidates can only be one. There are a lot of problems with that. In the end it's not much more than a team.
New Moose is a label. New Moose is a community of people who value good governance and effective, fair, accurate representation. We collectively decide on candidates to endorse. That may sound a lot like a party but there is no demand of exclusivity. We'll see New Moose Republicans, New Moose Democrats, New Moose Greens. There will be a lot that divides New Moose candidates from one another. But more important will be the fest things they share.
Labels not folders. That's not a bad model.