Donald Trump during an interview after a rally in Virginia Beach, Va., on Monday. (Steve Helber/ASSOCIATED PRESS)

Anthony D. Romero is executive director of the American Civil Liberties Union.

Donald Trump’s proposed policies, if carried out, would trigger a constitutional crisis. By our reckoning, a Trump administration would violate the First, Fourth, Fifth and Eighth amendments if it tried to implement his most controversial plans.

On immigration policy, there is simply no way a Trump administration could deport more than 11 million people within two years of taking office. To achieve such a feat, Trump’s deportation machine would have to arrest 15,000 people a day on immigration charges, seven days a week, 365 days a year.

The only way to accomplish this would be to shred the Fourth Amendment’s protections against unreasonable searches and seizures. To carry out such an order, immigration agents would have to engage in suspicionless interrogations and arrests, unjustified traffic stops, warrantless searches of workplaces and homes, and door-to-door raids in immigrant neighborhoods. There can be little doubt that agents would rely on racial profiling and target people of Latino and Hispanic descent disproportionately, violating their right to equal protection under the law regardless of their race or national origin.

After rounding up undocumented immigrants “in a very humane way, a very nice way” — that would inevitably include U.S. citizens by mistake — the Trump administration would run face-first into the due process protections afforded every person inside the United States under the Fifth Amendment. It is inconceivable that 11 million undocumented immigrants could go before a judge in any reasonable amount of time. The immigration system is already seriously backlogged and under-resourced, with immigrants facing removal already waiting 635 days for an immigration hearing.

And if Trump keeps them locked up, as he has proposed, he’ll deprive these people of their liberty — possibly for years — without due process of law. The Southwest border region under Trump’s proposals would become a police state.

In the realm of counterterrorism policy, Trump wants to do many unconstitutional, “frankly unthinkable” things. He would cast a dark shadow of suspicionless surveillance over Muslim communities and their houses of worship, simply because of their faith. By doing so, the Trump administration would infringe upon American Muslims’ First Amendment right to exercise their religion freely without fear or intimidation, as well as trespass against the establishment clause, which forbids the government from singling out certain religions for disfavored treatment.

This was already tried by the New York Police Department, with disastrous results. The NYPD’s Muslim surveillance program struck fear into the hearts of Muslim New Yorkers and made them less trustful of the police. Afraid of informants and undercover cops, mosque attendance declined. People watched what they said and mistrusted each other; some even went so far as to change their dress and trim their beards to look less Muslim. In its settlement of an ACLU lawsuit against the program, the city explicitly recognized that law enforcement can do its job without resorting to discriminatory practices. But Trump wants to resurrect this unconstitutional program and take it national.

Donald Trump called for a "total and complete shutdown" of Muslims entering the U.S. in December. But since then, his commitment to a "total and complete shutdown" has wavered repeatedly. Here's how. (Peter Stevenson/The Washington Post)

And his proposals don’t stop there.

In a misguided effort to prevent foreign attacks on the United States, Trump has proposed temporarily banning Muslims from entering the country and reintroducing torture. But once again the Bill of Rights constrains him. While the president does in fact have a lot of authority in immigration matters, the office can’t violate the First Amendment by unfairly singling out an entire group of people, based on their religion, for collective punishment.

Then there’s torture, the tool of tyrants. Although the George W. Bush-era torture program has been widely discredited as barbaric and ineffective — not to mention illegal — Trump has been unequivocal that he would bring back waterboarding and “a hell of a lot worse than waterboarding.” Waterboarding, along with the rest of the Bush administration’s “enhanced interrogation techniques,” violates the Eighth Amendment, which prohibits the government from inflicting cruel and unusual punishments, and international law. The same goes for methods he would approve that go “beyond waterboarding.”

Perhaps Trump’s most ignorant proposal, though, is his promise to “open up our libel laws” so that when the media writes things he doesn’t like, “we can sue them and win lots of money.” This is preposterous. There are no federal libel laws to “open up.” Legal claims for libel arise under state laws, over which a President Trump would have no control. But his proposal is nothing to laugh about, because it shows his contempt for First Amendment values and the free press.

For 96 years, the ACLU has not opposed or supported any candidate for office. We are not going to start with Donald Trump. But in the face of such an agenda, our job will be to muster all the legal arguments we can to derail and deter the presumptive Republican nominee’s patently anti-civil-liberties proposals should he become our nation’s 45th president.

If Trump does win the White House in November, the Constitution and the system of government it created will survive his presidency. Our institutions — particularly our courts — are stronger than the will of one man. But we need to be prepared because the very freedoms guaranteed by the Constitution could come under a sustained attack by a President Trump in the Oval Office.

If that day comes, make no mistake: We’ll be seeing him in court.