Washington (CNN) The legal confrontation over Donald Trump's immigration national emergency is becoming the most important test yet of his vision of an unfettered presidency immune to norms that check executive power.

The President hit back Tuesday after 16 states filed a lawsuit to stop his declaration aimed at redirecting funds already allocated by Congress for different purposes to build his border wall. The structure was the ideological anchor of his campaigns, rooted in claims that an "invasion" of undocumented migrants and criminals is swamping America.

"As I predicted, 16 states, led mostly by Open Border Democrats and the Radical Left, have filed a lawsuit in, of course, the 9th Circuit! California, the state that has wasted billions of dollars on their out of control Fast Train, with no hope of completion, seems in charge!" Trump tweeted.

The new legal fight has revived questions about Trump's expansive view of his own power and his frequent attempts to evade legal, political and constitutional restraints on his actions that add up to a more untethered notion of the presidency than most of his modern predecessors.

A profound question when Trump entered the Oval Office was whether his unruly, improvisational nature would be tamed by the magnitude of his new responsibilities and codes of presidential behavior framed over more than two centuries.

Or would Trump, a rambunctious, ego-driven outsider who never follows the rules, change the office itself by establishing precedents that his successors would eventually use to justify their own flexing of presidential power?

It's too early to assess Trump's long-term impact on the office of the presidency, a judgment that will be shaped by how his rule ends, after one or two terms, and the final conclusions of the Russia investigation.

But two tumultuous years, and six consequential weeks early in 2019 , suggest that many of the normal codes and conventions that governed the presidency for decades are suspended in the time of Trump.

He has lived up to his promise to his voters to disrupt the Washington establishment and the Western global consensus. Now, thwarted by a new Democratic House and the arcane checks and balances of the Senate, Trump is claiming new executive power to reconcile his hardline vows on immigration.

Trump's declaration of a national emergency to fund his border wall represents one of the boldest grabs for presidential authority in generations and caps what is now a lengthening record of contempt for the regular political order.

His straining against norms is not confined to his duels with Congress.

Trump's verbal torching of the institutions of his own government like the Justice Department and the FBI appears to be becoming more intense as Robert Mueller's special counsel probe grinds on.

One of Trump's most enduring strategies is his willingness to stake out easily disprovable positions if they support his political goals -- another way that he is unencumbered by the constraints of many of his predecessors. In a new manifestation of his resistance to objective fact, he is now openly trashing the data collected by his own agencies when it doesn't support his hunches on what he claims is an "invasion" of undocumented migrants.

He's even insisting he's already building his border wall -- reflecting the potential political price he may pay for failing to honor his top 2016 promise.

"I use many stats. I use many stats," Trump told a reporter who challenged him with official government data on drug trafficking last week. "Let me tell you, you have stats that are far worse than the ones that I use."

Awkward silence

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Trump's assault on the international system -- a step no President since the end of World War II would have dreamed of taking -- is widening. He's undoing trade deals, nuclear pacts and pressuring estranged alliances that underpin decades of US power in pursuit of his "America First" creed.

Europe's feelings were summed up by the stony, embarrassing silence when Vice President Mike Pence brought greetings from Trump to an annual national security conference in Munich over the weekend.

In his jarring news conference on Friday, Trump blasted away at the institutions that mold a free society -- including constitutional principles, the freedom of the press and the independent judiciary. He even publicly envied China's record on extra-judicial executions in an open rebuke of traditional US values.

And Trump has several times , that we know about, prized the counsel of Russian President Vladimir Putin over that of his own spy chiefs. He bristles when he's challenged on his world view as the roster of ex-administration officials shows.

One Trump ally, Newsmax CEO Chris Ruddy, told CNN's Christiane Amanpour Monday that the buzz around the White House is that Director of National Intelligence Dan Coats may be in danger after contradicting Trump's national security policies in a recent congressional hearing.

"There's a feeling that maybe there needs to be a change of leadership in that position," Ruddy said.

If Trump sacks Coats for insubordination, it will be a fresh example of how the President appears more untethered from personal, political and behavioral guardrails than any commander in chief in modern history.

Trump's coming second summit with North Korean leader Kim Jong Un appears as much motivated by his personal desire for a political win -- or a Nobel peace prize -- as any sign that their first meeting made much progress towards denuclearization.

His administration, which has shed staff at a historic clip, now looks more and more like the top-down, family business staffed by loyal retainers that characterized his real estate empire.

As his trampling of Republican anxiety about a national emergency showed last week, Trump's not much worried about putting his own party in unpleasant political spots.

His emergency declaration is in itself an expression of contempt for congressional power and is different than previous emergency declarations since he plans to spend money already allocated by lawmakers for other purposes to build a wall they refused to fund.

And Trump, who once said he knew more about ISIS than his generals, is not partial to military advice that contradicts his own views -- such as the Syria withdrawal plan that has alarmed top military commanders.

Trump: 'I want to go faster'

JUST WATCHED Cooper: Trump's 'urgency' has been 2 years in the making Replay More Videos ... MUST WATCH Cooper: Trump's 'urgency' has been 2 years in the making 05:12

Trump's explanation for choosing a national emergency last week to build his wall might have undermined his legal case for bypassing Congress in what may be a new effort by the courts -- one of the few roadblocks to Trump during his first two years in office -- to frustrate the President.

But his remark was revealing about a presidency rooted as much in personal gratification and a desire to spark outrage as a long-term ideological program.

"I wanted to do it faster. I could do the wall over a longer period of time, I didn't need to do this, but I'd rather do it much faster," the President said.

Other presidents have declared national emergencies. Some, such as Richard Nixon, have been erratic and incoherent in public. Franklin D. Roosevelt, seen as one of history's best presidents, made ambitious power grabs. Barack Obama dodged Congress with his "pen-and-phone" strategy of executive orders. Theodore Roosevelt made the presidency an extension of his boisterous and restless temperament. Andrew Jackson harnessed the power of flaming populism and Trump has professed to admire Old Hickory.

But it's hard to find a historical precedent for a commander in chief as volatile, publicly egotistical and apparently oblivious to constitutional norms as Trump.

Now that most of the restraining influences -- like James Mattis, the former defense secretary, or Rex Tillerson, the ex-secretary of state -- have left the administration, there are few internal limitations on Trump.

"Donald Trump doesn't have a containment vessel," said Timothy Naftali, a presidential historian at New York University. "It is a perfect storm for the presidency."

What the leader says goes

JUST WATCHED Trump defends declaring national emergency for border wall Replay More Videos ... MUST WATCH Trump defends declaring national emergency for border wall 04:29

For Trump's critics, America is heading down a dangerous autocratic path: It hardly seems likely that the President, with a taste for going it alone on a national emergency, will rein himself in.

Yet the fact that Trump, despite never cracking a 50% approval rating in most polls, remains a viable political force and may have a route to re-election, suggests that a substantial block of millions of Americans like what they see.

To Trump voters, the President is hacking away at a political system and governing structure they have come to believe does not represent them, after long years of economic hardship and endless foreign wars.

His complaints that foreign nations are bleeding the US dry are popular among voters tired of foreign engagements -- a feeling that is also traceable in the Democratic base as the 2020 campaign begins.

Trump's relentless base-pleasing strategy has intimidated his fellow Republicans, further loosening checks on a presidency that until recently benefited from a pliant Congress dominated by the GOP.

Republicans, such as Sen. Lindsey Graham of South Carolina, appear to have concluded that the way to avoid a primary fight is to embrace Trump -- testimony to the power of the President with the base.

"When the leader says do something, there's become the tendency to do it," former Ohio Gov. John Kasich, now a senior CNN political commentator, said on "New Day" on Monday.

"There has been more allegiance to the leader than I am sort of used to," the Ohio Republican said. "When I was in Congress there were times when we just told the leadership, 'We don't agree with you and we are going to do what we have to do.'"

Still, it's likely that some Republicans will peel away from the President when a resolution to terminate his state of emergency comes up in both chambers, though few observers predict a veto-proof majority.

Relying exclusively on a vocal, if engaged, minority will pose complications for Trump's re-election hopes.

And the fact there will be debate on the state of emergency at all suggests that from now on -- with Democrats running the House -- Trump will not have things all his own way, especially as a new oversight operation by committee chairs gears up.

"We have got to keep in mind that not every institution has been Trumpified," said Naftali. "The American people went to the polls in November and they voted in a Democratic majority in the House. That is a big deal."