Historically, Montana has had a more union background coupled with a sort of libertarian streak. Also, because of the state’s low population, retail politics were a lot more effective. The Democrats in Montana are more pro-gun statewide, and more conservative on some social issues (though some libertarianism mixed in). This meant the Democrats statewide had a lot of wiggle room, but the national party is not a good fit.
You mean Montana Democrats tend to be more moderate, like Jon Tester and Steve Bullock?