As any "union" endorsed by the democrat-communists itself would tilt towards communism, this is a backdoor attempt to impose a political shift upon the state National Guards -- even in [what are still the so-called] "conservative" states.
I would encourage the state governments to oppose such a move. As in,
vigorously oppose it.
Otherwise, the red states are going to lose whatever state/local control they retain over their own Guard units.