The military will not obey.
The military doesn’t have the numbers.
The military plus Federal law enforcement doesn’t have the numbers
The military plus Federal law enforcement plus state law enforcement doesn’t have the numbers
The military plus Federal law enforcement plus state law enforcement plus local law enforcement doesn’t have the numbers.
And keep in mind that throughout that list there will be a lot of people who will refuse to go along. As you get further down in the list the chances that people will refuse to go along will grow. There are LOTS of local law enforcement leaders in flyover country who have explicitly stated that they will not comply with any attempt to Federalize them.
Nationwide martial law just isn’t going to happen. The result wouldn’t be civil war, it would be the chaos of simple non-compliance.
I believe you’re right. However . . .