A constant refrain we now hear is that President Trump’s order to finance the wall is “unconstitutional” and “violates the separation of powers.” That is not the case. Richard H. Pildes, a professor of constitutional law at New York University, wrote on March 14 the clarifying article, “How the Supreme Court Weakened Congress on Emergency Declarations.”

Here are his salient points:

Trump’s declaration of a national emergency to build the wall derives from that singular authority in the National Emergencies Act (NEA), passed by Congress in l976. Since then, presidents have resorted to the NEA 58 times. In each case, the president—Democrat and Republican—spent funds not appropriated by Congress and the Supreme Court did not overturn the action. Pildes notes, “Courts are uncomfortable when asked to second-guess presidential judgments in areas such as national security, foreign affairs and emergencies.” The courts are not experts on these matters.

Pildes cites the key Supreme Court decision, Immigration and Naturalization Service v. Chadha, which declared, he says, that “legislative vetoes are unconstitutional”—including vetoes of actions under the National Emergencies Act, the basis on which Trump acted.

Pildes adds, “Congress cannot act through a legislative veto but can act only by passing a new law.” But the horse was out of the barn for Trump: he acted on the authority of the NEA. Chadha, says Pildes, “must give Trump the chance to veto Congress’s disapproval” of his unilateral action. He issued a veto, for which, Pildes further explains, a “two-thirds majority in each chamber [is required] to override....” This override is not likely to happen: in the Senate, 59 members voted against Trump’s declaration of a national emergency; a two-thirds supermajority would require 67 votes. In the House, 242 voted against Trump’s action, a two-thirds supermajority requiring 290 votes.

Pildes says the NEA “does not define what constitutes an emergency.” A non-definition goes to the president’s advantage. Trump neither violated the Constitution nor violated the separation of powers. His unilateral action was a constitutional power ceded to him by an act of Congress (the NEA) in l976 and used by presidents on both sides of the political aisle 58 times. President Obama, for example, used the act to transfer funds without congressional authority to his health care act.

The final resolution now will go to the courts, surely ending up in the Supreme Court. Now here’s the rub: we know that members of the Supreme Court often make political rather than legal decisions. The Court is now composed of four liberals and five conservatives. Jeffrey Toobin, legal analyst at CNN, was on the mark when he observed, “When it comes to the core of the Court’s work ... it is ideology, not craft or skill, that controls the outcome of cases.” Similarly, Richard A. Posner, the great conservative judge and law professor, has written, “It is rarely possible to say with a straight face of a Supreme Court decision that it was decided correctly or incorrectly.” Constitutional cases, he added, “can be decided only on the basis of a political judgment, and a political judgment cannot be called right or wrong by reference to legal norms.”

If the Supreme Court acts legally rather than politically in following the Chadha precedent, the vote could be 9-0 in support of Trump’s unilateral authority to declare an emergency and transfer funds to defray costs. Why do I feel somehow that the vote will be 5 to 4?