CNN  — 

President Joe Biden is taking his first major steps toward decriminalizing marijuana, fulfilling a campaign pledge to erase prior federal possession convictions and beginning the process of potentially loosening federal classification of the drug.

Biden on Thursday pardoned all prior federal offenses of simple marijuana possession, a move that senior administration officials said would affect thousands of Americans charged with that crime.

The announcement comes a month ahead of critical November elections that will determine control of Congress. Some candidates – in particular Pennsylvania Democratic Lt. Gov. John Fetterman, who is running for his state’s US Senate seat – have made the issue of marijuana legalization central to their campaigns. When Fetterman and Biden met last month, the candidate said he would raise the issue with the President. At the same time, Democrats have sought to rebuff allegations they are soft on crime, an issue that has risen to the top of some voters’ agendas in certain swing districts.

As part of the announcement, Biden also encouraged governors to take similar steps to pardon state simple marijuana possession charges, a move that would potentially affect many thousands more Americans.

And the President will task the Department of Health and Human Services and Attorney General Merrick Garland to “expeditiously” review how marijuana is scheduled under federal law, the first step toward potentially easing a federal classification that currently places marijuana in the same category as heroin and LSD.

“No one should be in jail just for using or possessing marijuana,” Biden said in a video announcing his executive actions. “It’s legal in many states, and criminal records for marijuana possession have led to needless barriers to employment, housing, and educational opportunities. And that’s before you address the racial disparities around who suffers the consequences. While white and Black and brown people use marijuana at similar rates, Black and brown people are arrested, prosecuted, and convicted at disproportionate rates.”

“Too many lives have been upended because of our failed approach to marijuana. It’s time that we right these wrongs,” the President said.

The moves Biden announced Thursday stop short of full decriminalization, which has enjoyed growing support among both political parties. But they are the first significant steps taken by a US president toward removing criminal penalties for possessing marijuana.

The President and a small circle of White House aides had been wrangling for weeks over the changes, complicated both by Biden’s own personal skepticism about decriminalization and not wanting to dictate changes to the Justice Department.

Biden’s own view on marijuana is a product of both his age and the years he spent as the chairman of the Judiciary Committee in the Senate working on crime bills. During the 2020 campaign, aides argued that he was waiting for new studies to come out that would inform a shift in his position – but even without any such studies, Biden was eventually moved by arguments about the lack of fairness and justice, particularly along racial lines.

White House aides were also watching the calendar with the midterms in mind, hoping that the changes long sought by criminal justice advocates will help build enthusiasm among Black voters, younger voters and a wider array of core Democratic voters.

Senior administration officials declined to say how quickly the review might be completed that would lead to further steps toward decriminalization.

“The process will take some time because it must be based on a careful consideration of all of the available evidence, including scientific and medical information that’s available,” one senior official said.

In his statement, Biden wrote that certain rules on marijuana would remain in place, even if the drug is descheduled.

“Even as federal and local regulations of marijuana change, important limitations on trafficking, marketing, and under-age sales should stay in place,” he said.

Marijuana is illegal under federal law, even as individual states have moved toward legal use for recreational and medical purposes. Under the 1970 Controlled Substances Act, marijuana is listed on Schedule 1, meaning it has “no currently accepted medical use and a high potential for abuse.”

That has left some users open to prosecution, even in places where marijuana use is legal.

Biden’s pardons will be issued through an administration process overseen by the Justice Department, a senior administration official said. Those eligible for the pardons would receive a certificate showing they had been officially forgiven for their crime.

Officials said there are currently no Americans serving prison time solely on federal simple marijuana possession charges. But they said the number who had been charged with that crime was north of 6,500.

As a candidate, Biden stopped short of endorsing legalization of marijuana for recreational purposes. But he did adopt a stance toward decriminalization.

“No one should be in jail because of marijuana. As President, I will decriminalize cannabis use and automatically expunge prior convictions,” he said during the presidential campaign.

Loosening federal rules on marijuana has gained steam in recent years as the drug is legalized in a growing number of states. In late 2020, the House passed a measure that would decriminalize marijuana at the federal level, though it wasn’t taken up in the Republican-controlled Senate.

This story has been updated with additional reporting.

CNN’s Isaac Dovere contributed to this report.