First, Congress should restrict when and how the White House intervenes in law enforcement actions, giving teeth to the norms of the post-Watergate era. One model for such legislation is a reform born out of President Richard Nixon’s abuse of the I.R.S. to target enemies. Congress made it unlawful for certain officials, including the president, to “request, directly or indirectly,” any I.R.S. officer or employee to, in effect, weaponize a taxpayer audit. Congress could apply that approach by prohibiting a president from intervening in individual law enforcement proceedings — or at a minimum require notification when a president or members of the White House staff do so. Such a rule would have imposed an additional bar, for example, on the president trying to get the Department of Justice to block the AT&T-Time Warner merger in retaliation for CNN’s coverage, or from trying to investigate or prosecute political opponents.

Second, Congress should ensure that if the president issues or even dangles pardons in an attempt to block an investigation into his own interests, legislators will receive documents regarding the underlying investigation (once it’s concluded). This will both ensure accountability and deter bad faith behavior. Representative Adam Schiff’s Pardon Abuse Prevention Act provides a good start; it could be supplemented to apply to so-called dangled pardons and to force disclosure of discussions with pardon seekers in investigations implicating the president.

Third, Congress can make it harder for the government to mislead the public. A little-known law called the Information Quality Act creates a requirement that federal agencies ensure the quality, objectivity, utility and integrity of information they provide to the American people. Strengthening the act so that it applies to the president would help expose disinformation and make it more difficult for presidents to take executive actions based on false “determinations” and “findings.”

Finally, Congress should prohibit the president from using federal law enforcement powers to interfere in an electoral campaign. Procedures designed to check some such activity exist in the United States Attorneys Manual, but that merely compiles prudential guidelines. Congress should harden these rules and expand them to cover other law enforcement agencies (such as the Department of Homeland Security). It could require a Civil Service process to approve sensitive actions around campaign season.

An even stronger measure could require early-stage confidential judicial approval before a law-enforcement action that might impact the outcome of an election could be taken. Such reforms would make it harder for a president to abuse power — such as by timing investigations or announcements to affect a political campaign, using the security clearance process to silence critics, sending immigration authorities to polling places or intervening in Secret Service activities to protect candidates and events.