Since Election Day, according to Forbes, stock prices of private prison companies have risen faster than the share price of Tesla. (A stun gun company’s stock has, too.)

Private prison companies, after all, are key to the incoming administration’s mass deportation drive. If Donald Trump and his aides go through with their plans to seize millions of people, they need to find somewhere to put them as they are processed. Hence the good times ahead for private prison companies, which will be enlisted to build detention facilities.

Immigration is a fraught topic. We are a nation of immigrants and also a nation of laws. Americans from across the political spectrum recognize that the immigration system has not been reformed in decades. More should be done to secure the border and address the overwhelmed asylum system. We don’t know how far Trump and his squad will go. It is far easier to tweet about deporting millions of people than to actually do it. Mass roundups — without consideration of the capacity of our legal system or the unique situation of each individual and family — would tear apart families, violate our ideals of due process and equal protection, and upend the economy. The indications are, though, that Trump’s campaign trail threat that it will be “a bloody story” should be taken both seriously and literally.

On Sunday, conservative activist Tom Fitton proclaimed on Truth Social that Trump “will declare a national emergency and will use military assets to reverse the Biden invasion through a mass deportation program.” At around 4 a.m., Trump replied, “TRUE!!!”

As I’ve described before, the Brennan Center’s experts have mapped out the ways that presidents can wield little-used laws to unlock astonishingly broad powers. But even these emergency powers, which have inadequate restrictions, must be subject to the rule of law.

The Posse Comitatus Act generally bars the use of the military on American soil. That is a core element of a liberal democracy. But other dusty and obscure laws provide exceptions to that rule. Over the past few months, we’ve explained those laws and the risks they pose.

Trump has threatened, for example, to use the Insurrection Act. (No, that’s not where he gets to stage another insurrection.) It is an amalgamation of laws that lets presidents use the military to help civilian authorities when they get overwhelmed by unrest. Although there are rare situations when this authority is necessary, the Insurrection Act has not been meaningfully updated in more than 150 years. As my colleague Joseph Nunn points out, the law is dangerously overbroad and ripe for abuse. It grants the president nearly limitless discretion to deploy federal troops domestically, and courts have been excessively deferential to the executive in the past. And the federal judiciary is increasingly obsequious to Trump and his followers.

Trump has even said that he will use the last remaining part of the Alien and Sedition Acts of 1798 — laws decried by Thomas Jefferson as reflecting a “reign of witches” — to treat immigrants as an invading army. The law has been used only three times, most recently to intern Japanese and other foreign nationals during World War II. Its use would be flatly illegal, since the statute allows its use only when the nation is at war with a sovereign government. (Though judges in the past have been reluctant to overrule the executive’s judgment, as my colleague Katherine Yon Ebright reports.)

Then there’s the National Emergencies Act, a 1976 law that gives presidents vast power with few guidelines about what constitutes an emergency. My colleague Liza Goitein has written and testified for years about how this law can be abused — for example, when President Biden wrongly tried to use it to cancel student debt. Staunch conservative Sen. Mike Lee of Utah has also called for change, noting that “this kind of lawmaking-by-proclamation runs directly counter to the vision of our Founders and undermines the safeguards protecting our freedom.”

Trump wielded the National Emergencies Act to steer funds to his half-hearted effort to build a border wall. Stephen Miller last year told the New York Times that this time around, the law will be used to redirect funds to build “‘vast holding facilities that would function as staging centers’ for immigrants as their cases progressed and they waited to be flown to other countries.”

All of these statutes give presidents too much power. All need to be repealed or reformed, as we have argued for years, working with conservatives and liberals to press for change. But all continue to be subject to the Constitution and the rule of law. We are now working with coalition partners to prepare legal challenges to abuses of these laws.

Judges in courtrooms across the nation will soon face a test. Will they use their power to enforce long-standing protections for individuals? Will they uphold the rule of law? Or will they bow to political pressure and allow the executive to expand its already ample power?

All this will unfold not in some distant future, but just weeks from now. The Brennan Center will do our part, using our years of expertise on these once-arcane topics to fight for the Constitution.