JFK: "War Will Exist Until That Distant Day When..."

Yet we look to the warrior for protection, when the enemy is at the gates.

To whom do we look when the enemy is inside the gates?

Please read the first link at:
Lincoln Predicted That The United States Would "Live Through All Time Or Die By Suicide"
http://paxonbothhouses.blogspot.com/2018/04/lincoln-predicted-that-united-states.html

Posse Comitatus Act of 1878

And they are still warriors.

I'm not sure why you mention the Posse Comitatus Ac of 1878.

Here is a significant 20th century modification of the original law.

In the mid-20th century, the administration of President Dwight D. Eisenhower used an exception to the Posse Comitatus Act, derived from the Enforcement Acts, to send federal troops into Little Rock, Arkansas, during the 1957 school desegregation crisis. The Arkansas governor had opposed desegregation after the U.S. Supreme Court ruled in 1954 in the Brown v. Board of Education that segregated public schools were unconstitutional. The Enforcement Acts, among other powers, allow the president to call up military forces when state authorities are either unable or unwilling to suppress violence that is in opposition to the constitutional rights of the people.[5]
https://en.wikipedia.org/wiki/Posse_Comitatus_Act

If you don't understand by now, I can't help you.