Last week’s revelation that Attorney General Jeff Sessions was plotting to target medical marijuana providers was largely obscured by his testimony before the Senate Intelligence Committee the next day. In a letter written to Congress on May 1, Sessions argues that because marijuana remains illegal under the controlled substances act, representatives should disregard longstanding protections against the prosecution of medical cannabis. These protections had just been renewed as part of a budgetary bill two days prior. It’s no coincidence that when the bill hit President Donald Trump’s desk on May 6, he included a signing statement that largely echoed the attorney general’s sentiments. On May 10, Sessions outdid himself when he issued a memorandum calling on US Attorneys to seek the harshest punishment allowed by law when prosecuting drug crimes, directly overturning the more lenient sentencing guidelines pushed forth by Eric Holder in 2013.

This threatens to undo significant progress that drug war opponents have made in recent years. Since Colorado voters made the Rocky Mountain State the first to legalize recreational cannabis in 2013, eight other states have followed suit. Added with the 21 states that allow medicinal cannabis, 60 percent of Americans live in a jurisdiction that has legalized marijuana. Moreover, former President Barack Obama commuted the sentences of over 1,000 non-violent drug offenders—more than any previous president.

In the current political environment, ramping up the War on Drugs would cause backlash for both the Trump administration and the GOP. In 2018, incumbent Republicans in states that have legalized marijuana would be forced to answer for an administration intent on disregarding the will of voters. Conversely, any Democrat running on a pro-marijuana platform would gain an instant boost in support as well as financial backing from an increasingly profitable cannabis industry. Come 2020, the issue would also give a boost to Democratic presidential candidates—such as Bernie Sanders and Kamala Harris, both of whom have expressed support for legalization.

Even if Trump loses in 2020 and these policies are overturned by a future administration, their impact over the next four years could prove devastating. If Sessions’ memo is followed by federal prosecutors, it would mean an increase in the enforcement of mandatory minimum laws, which remove judicial discretion and carry automatic 10 and 20 year sentences. Prior to Holder ratcheting back enforcement of these laws, they led to disproportionate sentences on numerous occasions. In one instance, a man was sentenced to a triple life prison sentences merely for introducing two drug dealers to each other. In another, a man was sentenced to a 42-year prison term for selling crack, a sentence the judge was obligated to impose under the “three strikes law” because he had two previous misdemeanor arrests for selling pot.

Increased enforcement of medical marijuana laws will lead to more horror stories such as these and will further increase the U.S. prison population, which is already the largest in the world. For medical cannabis users, many of which suffer from debilitating health conditions, a federal crackdown would make it more difficult for them to get the relief they need. It could also increase the risk many users already face of losing child custody.

For drug war opponents, the ultimate goal is that Congress pass a law decriminalizing marijuana at the federal level. This would be the only surefire way to both restrain Sessions and ensure that somebody of his ilk never again sets their sights on the War on Drugs.