This piece was published on Thursday. On Friday night, Donald Trump pardoned Joe Arpaio.

On Tuesday night, Donald Trump all but promised he would pardon disgraced Arizona sheriff Joe Arpaio, who was convicted of criminal contempt three weeks ago. “I won’t do it tonight,” he said. “But Sheriff Joe can feel good.” CNN is now reporting the White House has prepared the paperwork for Trump’s signature.

As many have warned, pardoning Arpaio – famous for racially profiling Latinos in Maricopa County – would be an endorsement of racism. There’s another reason the possibility of a pardon should trouble us: it reflects Trump’s deep disdain for the judiciary and its role in our system of checks and balances.

For years, Arpaio pursued a discriminatory policy of stopping and holding people for whom there was no reasonable suspicion of criminal activity. A federal court ordered him to stop in 2011, but he continued to detain people unlawfully for another 17 months.

Last month, a different federal judge found Arpaio guilty of willfully defying the court order – a criminal charge that was fairly easy to establish, given that Arpaio repeatedly bragged to national media outlets: “I’m not going to give it up” and “nothing has changed.” In short, Arpaio’s disregard for the law and the court’s order was flagrant and sustained.

Pardons do not intrinsically threaten the rule of law. Rather, the exercise of mercy is part of our constitutional design, and if anything presidents have used it too sparingly in recent years. But typically pardons are issued after a person has served some part of his sentence, shown remorse, and demonstrated a measure of rehabilitation, or to remedy some fundamental unfairness. There’s a thorough vetting process involving the justice department’s office of the pardon attorney to assess these factors.

Arpaio has not even been sentenced yet. He has defiantly maintained his innocence, despite all evidence to the contrary. And there is nothing unfair about a misdemeanor prosecution for his egregious conduct.

Moreover, Arpaio’s criminal activity goes to the heart of our system of constitutional rights and accountability. Private plaintiffs and the justice department sued him for violating the constitution. A court enjoined his illegal conduct. He then flouted the court’s order – repeatedly. Our system of rights and limited government works only if those in power follow judicial orders or are held accountable for violating them.

Disdain for judicial oversight, however, is central to Trump’s approach to public life. In 2016, Trump used race to question the impartiality of US district Judge Gonzalo Curiel, who had ruled against him in lawsuits brought by customers claiming they paid thousands for worthless Trump University courses.

Describing the Indiana-born judge first as “Spanish,” then “Hispanic,” and finally “Mexican,” Trump said Curiel should have recused himself in light of Trump’s pledge to build a wall along the US-Mexico border. (“We are building a wall. He’s a Mexican.”)

In February, after a Seattle-based judge blocked his ban on travelers from seven Muslim-majority countries, Trump insulted him as a “so-called judge” and even portrayed him as a national security threat: “Just cannot believe a judge would put our country in such peril,” he tweeted. “If something happens blame him and court system.” After the appeals court heard oral argument in the case, Trump bemoaned how “political” courts have become and compared the judges unfavorably to “a bad high school student.”

It was déjà vu in March. When a federal judge in Hawaii enjoined the president’s revised travel ban, Trump again lashed out against what he called “unprecedented judicial overreach.” Attorney general Jeff Sessions called into a conservative radio show to express amazement that “a judge sitting on an island in the Pacific” had the power to temporarily restrain the president.

In April, a San Francisco-based judge enjoined Trump from withholding federal funds from “sanctuary” jurisdictions. The ruling was predictable, not because of where the case was brought, but because the Tenth Amendment clearly prohibits the federal government from forcing state and local jurisdictions to carry out a federal program.

Nonetheless, the White House again went on the attack, claiming that “an unelected judge unilaterally rewrote immigration policy for our Nation” and slandering the decision as “a gift to the criminal gang and cartel element in our country, empowering the worst kind of human trafficking and sex trafficking, and putting thousands of innocent lives at risk.”

These statements are calculated to cut down the courts. By calling judges “political,” or asserting that their race makes them biased, or blaming them for violence in the country, the president is trying to drag them down from the world of facts and law and into the muck of ideological warfare. The argument doesn’t even have to make sense.

The Seattle judge is a George W Bush appointee, and the Hawaii judge was confirmed unanimously (Sessions himself voted yes). But the president casts them as partisans. His goal is to weaken the judiciary’s legitimacy with the public and thus its ability to curb executive misconduct.

Trump’s contempt for our system of checks and balances is broader still. It’s why he attacks Republican senators who disagree with him. It’s why he fired James Comey. It’s why he fumes about special counsel Robert Mueller and why his aides are digging for dirt on Mueller’s team.

Arpaio approached his job like he was untouchable. He violated people’s constitutional rights and flagrantly defied a federal court order meant to protect them. Given his disdain for restraints on his own power, Trump might find those actions admirable. But for anyone committed to accountability for government officials and a healthy democracy, the prospect of a pardon should be deeply disturbing.

Chiraag Bains served in the US justice department from 2010 to 2017 as a federal prosecutor and senior counsel in the Civil Rights Division. He is now a senior fellow at Harvard Law School’s Criminal Justice Policy Program and a Leadership in Government fellow with the Open Society Foundations