When former President Donald Trump was arraigned in a Manhattan criminal court on April 4, 2023, Judge Juan Merchan warned him to “refrain” from making social media posts that could incite violence or “jeopardize the rule of law.”

Hours before his arraignment, Trump reposted a since-deleted photo that featured him with a baseball bat alongside Manhattan District Attorney Alvin Bragg.

After Trump pleaded not guilty and was released from custody, he attacked Merchan and the judge’s family during a speech at Mar-a-Lago.

This isn’t the first time Trump has criticized those trying to hold him accountable.

He previously harshly spoke out against Bragg, the prosecutor leading the criminal case against him, calling him “corrupt” and a “radical left, Soros backed, district attorney.”

And he has targeted Merchan, claiming that the judge “hates” the former president and that he “strongarmed” one of Trump’s associates into taking a plea deal.

Trump has also questioned the integrity of the U.S. legal system itself, writing that it’s “impossible” for him to get a fair trial in New York City, presumably because the city’s population is heavily Democratic.

We are scholars of the presidency and U.S. courts. In our 2019 book, “The President and the Supreme Court: Going Public on Judicial Decisions from Washington to Trump,” we studied how presidents talk about court cases in their public statements.

We found that presidents criticize judicial decisions infrequently. And when they do, they tend to respectfully object to the decisions courts make rather than try to undermine their legitimacy or attack individual judges.

Trump, however, is not known to follow norms and does not abide by this one.

Here are three things to know about how Trump’s words regarding his criminal indictment can undermine the rule of law and confidence in the U.S. judicial system.

1. Trump’s attacks are bad for the rule of law

For a few different reasons, the language Trump uses to criticize those he perceives to be his legal enemies often has racist or sexist undertones and can undermine faith in the U.S. legal system.

Indeed, some studies suggest that Trump’s attacks on legal and political institutions may do just that.

For instance, research demonstrates that public approval of the Supreme Court dropped following Trump’s tweets calling U.S. District Judge James L. Robart a “so-called judge” after he halted Trump’s travel ban in February 2017.

We think that the country is not well situated to absorb further decreases in support for the rule of law. Americans’ faith in legal institutions has dropped dramatically in recent years because of various complex factors, including controversial Supreme Court decisions.

Public disapproval of the Supreme Court is at all-time high, with 58% of Americans disapproving of the court as of September 2022.

Similarly, people’s confidence in the criminal justice system has dropped over the past several years, with 43% of Americans indicating in 2022 they have very little confidence in the way the country handles crime. When former President Barack Obama’s term began in 2009, only 25% of people said the same.

If public support for the rule of law weathers the storm and serves as a check on Trump’s brand of vindictive politics — as it has been on past abuses of presidential power — then American legal institutions will prevail.

But if Trump’s relentless, aggressive attacks convince large swaths of the public that he is being unfairly treated, this may lead to their questioning all kinds of other legal decisions. The end result may be a further drop in confidence in the rule of law, at least among Trump’s supporters.

2. These attacks can be dangerous

Physical threats on judges and other court personnel are at an all-time high.

Some of this increase can be linked to Trump’s time in the White House, if not his behavior directly. Over the course of his presidency, the U.S. Marshals Service reports that inappropriate communications and threats against judges, prosecutors and other protected persons increased by about 50% — from 2,847 in 2017 to 4,261 in 2020.

Robart received a wave of threats after he granted a restraining order against Trump’s travel ban in 2017 and Trump tweeted about Robart. In response to Trump’s public attacks, Robart’s personal information was leaked on the internet and the judge received more than 100 death threats.

3. Trump’s criticisms are in a league of their own

When both Republican and Democratic presidents have criticized legal decisions they don’t like, they have generally followed a common playbook. Typically, presidents express respect for the judicial branch and the rule of law and explain their disagreement. They do not single out people and resort to personal attacks.

President Bill Clinton, who faced indictment for lying to a grand jury in 1998, followed this playbook when he took responsibility for his “personal failure” during an address to the nation, and referred questions about the investigation to his lawyers.

Although he opposed an independent prosecutor, he never criticized the prosecutor’s legitimacy.

Conversely, Trump routinely violated this norm by personally attacking individual judges and courts instead of expressing principled disagreements about their decisions based on a different understanding of law.

During the 2016 presidential campaign, Trump used racially tinged language when attacking the judge set to overhear the fraud trial of Trump University. Trump claimed that District Judge Gonzalo Curiel would be biased against him because he was of Mexican descent.

Given Trump’s long history of these type of vicious personal attacks on members of the legal community, it seems unlikely that we will see a radically different Trump now that he faces criminal charges for the first time in his career.

While this may help Trump raise more money for his presidential campaign, it may cost the country some faith in the rule of law, while putting legal officials in danger.

Paul M. Collins Jr. is a professor of legal studies and political science at UMass Amherst. Matthew Eshbaugh-Soha is a professor of American politics at the University of North Texas.

This article is republished from The Conversation under a Creative Commons license.