Brendan Nyhan is professor of government at Dartmouth College and an organizer of Bright Line Watch, a watchdog group monitoring the state of American democracy.

The calls for Donald Trump to release his tax returns began early during the campaign and never really let up. It was easy to assume he eventually would make good on his promises to turn them over. Every president since Jimmy Carter had released his taxes; Trump would have to do the same, right?

What we’ve learned since then, of course, is that Trump didn’t have to reveal anything. The Constitution doesn’t require disclosure; plenty of federal officials need to submit their tax returns to the Senate, but not the president. It’s just a norm.


One of the crucial lessons of the past year, turns out, is just how much of American politics is governed not by written law, but by norms like these. For instance, the president isn’t required to divest himself of his businesses, but previous occupants of the White House have followed this tradition. Carter even put his peanut farm into a blind trust to avoid conflicts of interest. By contrast, Trump handed the reins to his sons, maintaining the rights to directly extract profits from the trust that controls his business empire. It’s not illegal, but before this year, it was a line no modern president had crossed.

Social scientists have long understood the importance of norms—the unwritten rules and conventions that shape political behavior—but our political system has largely taken them for granted. As a result, we have been slow to recognize how vulnerable these informal constraints on power are to someone who refuses to follow rules that everyone else respects.

Trump’s assault on norms started during the campaign, when he encouraged violence among his supporters, attacked the ethnicity of a federal judge (a double norm violation) and called for the imprisonment of his opponent. Once he was elected, many observers assumed this pattern would cease: Surely there are constraints on this kind of behavior from the president.

There aren’t—or, at least, there are few formal ones. Many of Trump’s statements and behavior have no precedent in recent history, but they aren’t illegal. He openly admitted to firing James Comey as FBI director because of Comey’s investigation into Russian influence in Trump’s campaign—probably a legal act, but a violation of long-respected norms against political influence in the Justice Department. Similarly, Trump continues to visit and promote his businesses while in office, which would be prohibited for a Cabinet secretary, but is legal for the president. White House jobs for his children? Directly attacking the press? Railing about politics to military service members under his command? These were red lines so strong that they seemed to have the force of law, but no longer.

We normally count on politicians to restrain themselves out of fear of public consequences. But as Trump’s election showed, the polarization and partisanship of our era has weakened those guardrails. Democrats are sounding the alarm, but members of his own party have remained largely silent. Violating norms is part of Trump’s appeal to his core supporters. As a result, these violations are frequently dismissed as just another case of partisan disagreement. Boundaries on presidential behavior that both parties have previously respected are blurring, making further abuses all too easy to imagine.



Directly attacking the press? Railing about politics to military service members? These were red lines so strong that they seemed to have the force of law, but no longer.



Internal checks, too, have withered. The Office of Government Ethics previously relied on voluntary compliance from officials who served under past presidents, including both Barack Obama and George W. Bush. Under Trump, however, this norm, too, has been breached with little cost to the president or his appointees. Walter Shaub, the head of OGE, recently stepped down, frustrated at his ineffectiveness during the Trump administration. Shaub told the New Yorker, “To have OGE criticize you would have been a career-ender in the olden days—now it’s just lost in the noise.”

What happens when norms are shattered like this? One response is to write them into law. After Watergate, Congress created an independent special prosecutor role to guard against interference in investigations of the executive branch, and strengthened campaign finance regulations in response to abuses during the 1972 election. Similarly, after Franklin D. Roosevelt broke George Washington’s precedent of serving only two terms, the Constitution was amended to formally limit the length of a presidency. After Trump, Congress could well take similar steps like requiring presidential tax disclosures, strengthening conflict-of-interest protections and increasing independent legal authority over the executive branch.

Such laws will never be sufficient, however. As political scientists have long known, there is no way to formally prohibit every type of bad behavior in advance. Who could have anticipated that it might be necessary to criminalize collusion with a hostile foreign power on the release of hacked emails?

Ultimately, our country must therefore also rebuild respect for the informal rules of our political system. The fact that presidents have long separated business and politics voluntarily was a measure of how seriously they—and we—took the public trust. These conventions of behavior were virtually invisible to us precisely because so many public officials dutifully followed them, until now. As we have seen, these norms might be a fragile bulwark against a demagogue, but they also reflect a commitment to a set of shared rules and values that is an important indicator of the health of our politics. Without that commitment, preserving our freedoms will become a much more difficult and dangerous task.