“If there’s a concrete wall in front of you, go through it, go over it, go around it. But get to the other side of that wall.” —Donald Trump, 2004 commencement address, Wagner College, Staten Island, N.Y. (unearthed by “The Daily Show”)

For the time being, President Trump has toned down his threat to declare a national emergency to pay for his long-promised wall along the U.S.-Mexico border. Addressing a White House roundtable Friday afternoon, Trump continued to insist that he has the “absolute right” to issue an emergency decree. But, he added, “I’m not going to do it so fast.”

While Trump’s announcement is welcome news to anyone concerned with human rights and rational immigration policy, it’s important to remember that our 45th commander in chief can’t be trusted. As long as the president’s lips move, there’s a good chance he’s lying.

Even if he wasn’t prevaricating on Friday, he could change his mind in a moment, egged on by the likes of Sean Hannity and Rush Limbaugh over the airwaves, and encouraged by GOP senatorial apparatchiks such as South Carolina’s Lindsey Graham, who has become one of the president’s loudest enablers.

The problem, however, isn’t just that we have a mendacious crypto-fascist in the White House who looks to other crypto-fascists for counsel and succor. The problem is that the National Emergencies Act (NEA), passed in 1976 and which Trump would invoke to get his way, makes it easy for any president to declare emergencies. Trump’s threat to deploy extraordinary powers to counter a fake crisis on our southern boundary should spark a clarion call to reexamine, repeal and replace the NEA.

The NEA was designed to place congressional checks and balances on the emergency authority of the president, and to restore the separation of power between Congress and the executive branch. The act may have been well-intentioned as a post-Watergate reform, but in practice it has been a dismal failure.

Historically speaking, there is nothing new in Trump’s emergency posturing. Prior to the adoption of the NEA, American presidents issued scores of emergency orders, dating back to George Washington’s 1794 proclamation. Aimed at suppressing the Whiskey Rebellion (a rural uprising against the nation’s first excise tax) in western Pennsylvania, the first U.S. president’s declaration facilitated the mobilization of state militias.

In succeeding decades, other presidents invoked more sweeping powers. At the start of the Civil War, Abraham Lincoln suspended the writ of habeas corpus. During World War II, Franklin Roosevelt ordered the internment of Japanese-Americans. In the midst of the Korean War, Harry Truman attempted to seize the country’s steel mills to avert an industrywide labor strike.

Apart from the Supreme Court’s decision in Youngstown Sheet & Tube Company v. Sawyer (1952), which invalidated Truman’s takeover bid, federal courts have been reluctant to overturn presidential emergency declarations. In 1944, to cite perhaps the most egregious instance of judicial abdication, the Supreme Court upheld Roosevelt’s Japanese internment order in Korematsu v. United States. It wasn’t until last year—in its decision affirming Trump’s Muslim travel ban, ironically—that the high court officially repudiated the Korematsu case.

By the early 1970s, Congress had enacted some 470 statutes, delegating extraordinary powers to the president in times of crisis on issues ranging from public health, natural disasters and land management to national defense and security. A 1934 law still on the books even allows the president to shut down or take control of “any facility or station for wire communication” (arguably, the internet in the digital era) upon his proclamation “that there exists a state or threat of war … or other national emergency.”

As Elizabeth Goitein, co-director of the Liberty and National Security Program at the Brennan Center for Justice, writes in The Atlantic, the NEA was passed to “rein in this proliferation.”

Problematically, the act doesn’t define what constitutes an emergency. “The president,” Goitein explains, “still has complete discretion to issue an emergency declaration—but he must specify in the declaration which [statutory] powers he intends to use, issue public updates if he decides to invoke additional powers, and report to Congress on the government’s emergency-related expenditures every six months. The state of emergency expires after a year unless the president renews it, and the Senate and the House must meet every six months while the emergency is in effect ‘to consider a vote’ on termination.”

Thirty-one states of emergency are in effect today, according to Goitein. Many, such as the freeze on Iranian government assets imposed in 1979, have been regularly renewed. Goitein also notes that “during the 40 years the law has been in place, Congress has not met even once, let alone every six months, to vote on whether to end them.”

While there is little question that Trump has the legal authority to declare a state of emergency, it remains to be seen whether doing so will actually get him the money he wants for the border wall. It also remains to be seen whether the Supreme Court will step in, as in the Youngstown Steel case, to stop him.

Under the Constitution’s Appropriations Clause, Congress controls the power of the purse. It alone among the three branches has the authority to appropriate funds.

As a result, to secure funding for his wall, Trump will have to redirect federal funds that have already been appropriated for other purposes, but have not yet been spent. Some legal experts expect that Trump will attempt to tap into the Defense Department’s budget, invoking federal statutes governing military construction projects. The president might also try to withdraw relief funds earmarked for Puerto Rico, Texas, California, Florida and other states hit by recent natural disasters.

Any legal challenge to such maneuvers will face several obstacles, beginning with the question of “standing”—the requirement that a plaintiff must allege personal harm or injury in order to bring a lawsuit.

One possibility, according to University of Texas Law School professor Robert Chesney, is that House Democrats might establish standing as a legislative body, arguing that any border-wall emergency declaration and redirection of federal funds would violate the Appropriations Clause and undermine the role of Congress as a co-equal branch of government. Landowners along the border, following the lead of the steel companies in the Youngstown case, might also have standing to challenge Trump’s emergency order if the administration tries to seize their property to construct the wall.

Assuming that standing requirements are met, the challengers would have to persuade federal judges—and ultimately the Supreme Court—that conditions along the southern border don’t amount to a real emergency. Unlawful border crossings have dropped precipitously since 2000, most drugs enter the country through ports of entry, and border communities are among the safest in the nation.

Unfortunately, however, there is no binding legal definition of a national emergency.

The closest the Supreme Court has come to defining an emergency occurred in Home Building and Loan Association v. Blaisdell, dealing with mortgage lending and foreclosures. In the 1934 case, the court characterized the Depression-era emergency in housing and homeownership as a sudden, unanticipated disaster akin to a natural calamity like a fire or flood.

Because there are already crossing stations, walls, fences and other barriers along 654 miles of the 1,954-mile-long southern border and because immigration has long been a topic of high-level policy debate, the situation at the border cannot, objectively, be described as an emergency.

Getting the Supreme Court to agree, however, will prove a daunting task, especially in light of last year’s genuflection in the court’s travel ban ruling.

Worse still is the prospect that after pressing the emergency button for the border wall, Trump’s appetite for even more outrageous initiatives will expand exponentially until he destroys our democracy piece by piece, one phony national emergency at a time.