In a nation founded on a revolt against tyranny, the notion of American troops being sent onto domestic streets has always evoked a specter of liberty in peril.

This is why most presidents resisted such a step and why President Donald Trump’s insatiable zeal for doing so may be so consequential.

His attempts to send National Guard reservists into Portland, Oregon, and Chicago, Illinois, against the wishes of city and state authorities, has the potential to finally create the constitutional crisis his critics have feared for eight months.

It is testing how far Trump can push his Make America Great Again philosophy and his strongman “I alone can fix it” mantra. Originally unveiled at his first GOP convention in 2016, it runs like a spine through his two presidencies.

The transfer of reserve troops from red states such as Texas to Democratic cities will also deepen the chasm and the hostility between conservative rural and liberal urban areas that is an increasingly potent dynamic in America’s divided politics.

Ultimately, a cascade of administration threats and power moves by the White House; fierce pushback from Democratic mayors; and a thicket of legal challenges will show how far the law and the Constitution can contain a president who epitomizes many of the anxieties of the founders about how a politicized executive with a lust for power could threaten their republic.

As so often with the great controversies of the Trump era, the facts are obscured in misinformation, false claims, cumbersome legal arguments and the ambitions of big political players on each side.

But the core issue is quite simple.