Launching criminal investigations into an outgoing president would set a dangerous precedent. In this country, we don’t use the criminal justice system to punish political opponents. Trump has routinely threatened to prosecute his political rivals and led “lock her up” chants at his rallies. Those who recoiled from such behavior should think twice before encouraging Biden’s attorney general to start down that road.
This problem would be magnified by Trump’s apparent intention to run for president again in 2024. Trump and his supporters would inevitably characterize any investigations as a corrupt attempt by the Biden administration to “take out” a potential 2024 rival. If you think the political atmosphere was poisonous during the Mueller investigation, imagine what it would be like with the Biden Justice Department prosecuting Trump.
We also don’t prosecute political misdeeds that aren’t actually criminal. Many of Trump’s actions fall into this category. The past four years have showcased how much we have relied on unwritten norms to guide the behavior of presidents we assumed would act in good faith. Trump exposed the lack of any real legal backbone to many such norms. For example, he refused to divest himself of his businesses and repeatedly enriched himself through taxpayer-funded trips to his own properties. Such behavior was previously thought unthinkable, but no law expressly prohibits it. Outrageous? Yes. Sleazy? Yes. But likely not criminal.