A government-supremacist is an extreme statist. Not just someone who believes governing others to be a legitimate human endeavor but someone who assumes that political government is superior to and naturally above society and the individuals in a society.
In fact, they almost always conflate the State and society, even though those are opposites.
The government-supremacist uses phrases like “our/my president”, “our government”, “our military”, and assumes that everything should be decided and controlled in some way by the State. They believe government should always have a say and a plan. There is probably no aspect of life a government-supremacist would believe is always off-limits to government intervention or oversight.
A government-supremacist never doubts the legitimacy of the State even if questioning whether it sometimes goes too far in specific instances.
In any discussion of politics, government, legislation, or society, government-supremacists have the lowest possible amount of credibility. Their opinions can be dismissed– other than taking note of them as a warning of what they’d allow government to do to society… and to you.