President Trump's first constitutional crisis took a mere eight days to arrive.

The fight began Friday when Trump issued an executive order temporarily banning immigration from seven Muslim-majority countries — a sleight of hand whereby all immigration from those countries is banned, but then exceptions are made for non-Muslims. It was implemented immediately, without any legal review whatsoever (U.S. attorneys admitted in court they couldn't justify it), and caused immediate chaos. People whose visas were already approved were turned back, and at least at first, even green card holders coming from the targeted countries were denied entry.

Legal challenges filed by the ACLU and others got several quick victories in federal court. But federal Customs and Border Patrol officers reportedly refused to obey, and were continuing to do so as of early Monday morning. In one shocking instance, four sitting members of Congress from the D.C. suburbs went to the Dulles airport to demand that airport cops grant access to the people being detained, in keeping with the court order. But the airport authority's deputy police chief refused.

Here's what this means: Donald Trump's executive branch is defying the judiciary, even with the personal, in-person assistance of national legislators. He is attempting, in part at least, to overturn constitutional government in the United States.

This is not an exaggeration. In a republic, a professional legal corps gets to interpret the law as written by the elected representatives of the people, and the agents of state violence must obey their commands. In a tyranny, the leader does whatever he wants. That is what Trump, with the close counsel of his advisers Stephen Bannon and Stephen Miller, is trying to create.

This executive order is a relatively small action. Trump has not dissolved Congress, or proclaimed himself dictator for life. But obviously, what is stopping him from doing that is the general principle that the executive will obey the law. Once you've broken that, the way is short and easy to a full-blown tyranny.

This road was paved by many bipartisan actions before him. Snapping the neck of the rule of law is usually easiest when it's done by scapegoating some small, unpopular minority, and both Democrats and Republicans have partaken of policy bigoted against Muslims and refugees. Only last year Democrats were using an Islamophobic no-fly list to grandstand on gun control, and in 2015 Hillary Clinton was arguing that refugees from violence in Central America should be deported en masse. President Obama deported 2.5 million people as of 2015. That's more people than any other president, which hugely empowered the selfsame CBP in the process.

The imperial, increasingly lawless executive branch has also been built up over many preceding presidents. George W. Bush conducted illegal surveillance and torture by getting his pet legal hacks to write up nonsensical opinions justifying whatever he wanted to do, then keeping the justification secret. Obama scaled back that system slightly here and there, but he did not remotely conduct the root-and-branch reform to put the presidency back on a constitutionally sound basis.

Trump's defiance of the courts is going much further than Bush or Obama, of course, but he's demolishing norms that were already badly cracked because of them and their predecessors. It's important to remember the bipartisan nature of this history, because contrary to Obama partisans, defanging the executive branch will mean going far past the pre-Trump status quo to demolish a system that Obama protected and expanded.

Luckily, Trump's action also created mass protests in cities across the country. America's democratic and civic culture is far stronger than that strangled by Putin in Russia. It seems Trump later backed down on permanent residents — though the order was so chaotic that it's unclear whether that is actually happening. Many CBP agents seem to have taken that as license to carry out pre-existing anti-immigrant agendas.

Perhaps the most important question for the immediate future is what CBP and other law enforcement agencies will do. American cops have long had a case of creeping fascism, and both the largest police union and the Immigration and Customs Enforcement union endorsed Trump. If Trump orders these protests to be violently dispersed in violation of the Constitution, how will law enforcement respond?