The military and Federal police agencies simply lack the resources to pacify the entire country, especially with defections. Those defections allowed Franco to organize a successful overthrow of Spain's Marxist regime in the 1930s.
Deep State leadership will have to call on foreign military assistance. The Chinese, Russians, Iranians, and the Latin American Communist countries will oblige them, at a huge price. Also, Mexico may want to enter the show to recoup their territorial losses in 1836 and 1848. Remember that when the post-Roman Britons were threatened by Pictish and Gaelic invaders, they turned to the Angles, Saxons, and Jutes for military aid. Their warriors defeated the Celtic threat but then took over what became England, killing or driving out the natives.
Mexico would face the flip side of the Alamo in Texas.