Critics of Obama’s recent executive order on immigration legitimately worry that accepting its legality leads to unlimited presidential discretion over federal law enforcement. I think this concern is overstated. There are still some limits. But it is true that executive discretion has grown dangerously broad – not because of Obama’s most recent action, but because the enormously broad scope of federal law creates a situation where almost everyone has violated the law at some point, and only a small fraction of offenders can be prosecuted. The president thereby inevitably has broad discretion in deciding which ones to go after.

I. Why Accepting Obama’s Order Does Not Imply Unlimited Executive Discretion.

Timothy Sandefur worries, that my defense of the president’s order gives the president so much discretion “that no president would ever be in violation” of the Take Care Clause of the Constitution, which requires that he “faithfully” execute federal law. Not so. A president who uses executive power to harrass people who haven’t violated any law would be in violation of the duty to “faithfully” execute the law on the books. He would also be in violation if he chose targets for prosecution not based on the severity or importance of the crimes they committed but based on personal or political animus towards the accused. He would also be in violation if he attempted not only to refrain from prosecuting violators, but to decree that they had not violated the law at all, thereby precluding future presidents from going after the perpetrators as well. Obama has arguably done the latter in the case of his Obamacare waivers. But he did not do it in his immigration executive order.

There are other limits on executive discretion as well. For example, Congress can earmark funds for particular types of enforcement. If the executive branch agency does not spend the money as Congress wants, it could forfeit that money entirely. Congress could even condition funding for an agency based on its undertaking some enforcement actions or refraining from others. For example, it could adopt a law that cuts the budget of the relevant agency unless it deports X number of illegal immigrants in a given year.

The president also cannot use his discretion in ways that threaten individual rights protected by the Constitution. For example, he cannot choose which offenders to prosecute based on the the race, sex, religion, or political views of the potential defendants. The IRS’ selective targeting of conservative and Tea Party-aligned groups was illegal, because they were targeted based on their exercise of First Amendment rights.

II. Why Executive Discretion is Still Dangerously Overbroad – and what we can do about it.

These limitations still leave room for an enormous amount of executive discretion, which is readily subject to abuse. Given the current enormously broad scope of federal law, almost everyone has run afoul of it at one point or another. No president can target more than a small fraction of offenders. He or his subordinates must decide which few will be the ones they go after, which in turn creates tremendous scope for executive discretion. That power is easily abused, and easily used to treat one category of offenders more favorably than others. As I noted in my previous post, federal officials have for decades effectively declined to prosecute marijuana use and distribution on college campuses, but often take a tougher line against similar offenses elsewhere, especially in poorer areas.

This danger is exacerbated by the fact that Congress has enacted numerous laws that neither the political elite nor mainstream public opinion really wants to enforce to the hilt. If the DEA were to launch massive sting operations to root out marijuana use on college campuses, there would be a huge outcry. Similarly, I doubt that majority public opinion could stomach the draconian measures that would be necessary to round up and deport all or most of the 11 million illegal immigrants currently in the country. The reality that neither Congress nor the public really wants comprehensive enforcement these laws further creates further opportunities for executive branch selectivity.

As Josh Blackman points out, part of the difficulty lies in Congress’ delegation of so much power to the executive branch and its longstanding reluctance to do much to assert its own authority. Josh persuasively argues that Congress should do more to limit presidential discretion.

But the ultimate root of the problem is the enormously broad scope of federal law. Even if Congress were more assertive, it could not prevent the president from exercising extremely broad discretion in a world where almost everyone is a federal criminal, and he has to pick and choose a small fraction of those criminals to go after. If we truly want to limit executive discretion and selective enforcement of laws, the best way to do so is to cut back on the scope of federal law to the point where the president has the resources to go after all or most offenders. Better still, federal law could be limited to those activities for which there is a broad consensus that they really are serious offenses that cannot be left to the states, and must be targeted by the federal government. If a president still chose not to enforce them, or did so only selectively, he (and his party, if they choose to support his actions) would suffer a tremendous political backlash.

UPDATE: I responded to Timothy Sandefur in greater detail in an update to my previous post on Obama’s executive order.