President Donald Trump’s national emergency declaration to build a wall on the U.S.-Mexico border is an outrageous abuse of power, with dire implications for the future of our country. The idea that this president — or any president— is simply able to utter the magic word “emergency” and then circumvent the law and our Constitution is a profound threat to our democracy. It is imperative that Trump’s emergency declaration be overturned or invalidated.

Candidate Trump famously ran for office on the claim that he would build a wall on the border, paid for by Mexico. Mexico declined to accept the offer to pay for a wall it doesn’t want and rightfully perceives as a symbol of exclusion. So if Trump was to build the wall, it would have to be paid for with U.S. funds.

The U.S. Constitution is very clear about which branch of government has spending authority. It is the Congress. With Republicans in control of both houses of Congress during the first two years of his presidency, Trump made only a halfhearted effort to secure border wall funding, to no avail. And he appeared prepared to go along with a funding bill at the end of 2018 that again included no border wall funding.

However, Fox News commentators attacked him, and he suddenly decided that border wall funding was imperative. But Congress remained unalterably opposed. After a partial government shutdown that lasted more than a month, Trump again agreed to spending legislation that included no funding for the border wall.

More than two years into his presidency, and having been boxed into a corner by his Fox News allies, Trump then discovered a crisis at the border that he claimed necessitated invoking special emergency powers. Trump’s fake emergency has none of the aspects of urgency, suddenness or unexpectedness associated with genuine emergencies. As he said at the news conference announcing the emergency, “I didn’t need to do this.”

Nor are the factual premises of his claimed emergency true. Unauthorized immigration is not surging; in fact, it is down 75 percent or more from two decades earlier. Undocumented immigrants commit crimes at a lower rate than the general population. According to the Department of State, there is “no credible information that any member of a terrorist group has traveled through Mexico to gain access to the United States.” The Drug Enforcement Administration states that illegal drug traffic is channeled through legal ports of entry, not open border areas.

The only crisis at the border is the buildup in Mexico of families seeking asylum in the United States — but those people are seeking legal entry into the United States, and the crisis is due to the Trump administration’s refusal to afford them humane treatment.

No, Trump’s emergency declaration has nothing to do with any emergency. It is due entirely to his political problem of being unable to secure congressional appropriations to construct a needless wall that is a monument to racism and anti-immigrant sentiment more than anything.

It can’t be an emergency simply that the president is unable to win congressional approval of a campaign promise. And if it is, then presidents in the future will be able to invoke “emergency” with very few limits. Might this president declare “emergency” to deploy the military on the streets to maintain order and limit the right to protest? Might a future president declare “emergency” and thereby seek to address gun violence through unilateral action? It’s not hard to imagine such scenarios — which become much more plausible if Trump’s border wall emergency declaration is permitted to stand.

My organization, Public Citizen, and several others have sued to block the emergency declaration, claiming it exceeds the president’s power under the National Emergencies Act and violates the Constitution, which lodges spending power with the Congress. But we can’t count on the courts, which move slowly and historically are very deferential to presidential claims of national security.

Under the National Emergencies Act, Congress has the ability to pass a resolution of disapproval to override Trump’s declaration. The Democratic-controlled House of Representatives will almost surely pass such a resolution, and the Senate might as well. The Senate vote will test Republicans who have stated their opposition to executive overreach — will they stand for their stated principles, or will they simply accede to whatever Trump does?

To preserve Congress’ own power, but more important to protect our democracy and constitutional system, it is imperative that Congress act to override Trump’s unconstitutional emergency declaration.