Did the government of Grenada invite US forces in? No.
Did the government of Panama invite US forces in? No.
Yet let a flag-carrying, mob of invaders MARCH on our border, promising to illegally cross northward and every legal Beagle in DC puts starts rifling through the dustiest tomes, stroking their beards, waxing eloquent and tsk-tsk’ing about No Legal Mechanism.
When unarmed people with the will confront the mightiest army on Earth with NO WILL, there is NO CONTEST.
Uhh, you forgot that Gen. Mattis is involved.