The 2020 election is heating up, and one of the many issues the candidates have weighed in on is marijuana. Although the drug is illegal at the federal level, many states have legalized it on a medical and/or recreational basis, and efforts to remove the federal prohibition on the drug are gaining steam in the Senate. As such, many observers are wondering exactly where the 2020 candidates stand on marijuana legalization.

Marijuana policy is complex and multifaceted, and there are many ways in which a politician might be called "pro-marijuana." For instance, they might support de-scheduling the drug from the Controlled Substances Act (CSA); this would immediately end the federal prohibition on marijuana and, as a result, bring states that have already legalized it in compliance with federal law.

Alternatively, a politician could support legalizing medical, but not recreational, marijuana. Or, they could support retaining the federal ban but carving out an exception for states that have legalized it on their own; this is what the STATES Act, currently under consideration in Congress, would do. For politicians who support some form of legalization, there's also the question of whether to expunge the criminal records, and release from prison, those who've been convicted of marijuana-related crimes.

Recently, Sen. Cory Booker introduced the Marijuana Justice Act, a far-reaching piece of legislation that would end the federal ban on marijuana, expunge marijuana convictions, invest in job training for the marijuana industry, and cut funding for local police departments that disproportionately arrested people of color for marijuana-related crimes.

Here's a look at where the upcoming batch of presidential contenders stands on weed:

President Donald Trump Pool/Getty Images News/Getty Images While running for president, Trump claimed he believes marijuana legalization should be left up to the states, and in mid-2018, the president said he'd "probably" end up supporting the STATES Act if Senate Republicans allowed it to come up for a vote (which they haven't). Substantively, however, Trump has done nothing to advance marijuana legalization — and according to a report BuzzFeed News, his administration secretly established a "Marijuana Policy Coordination Committee" tasked with collecting "data demonstrating the most significant negative trends" of marijuana. Bustle has reached out to the White House for confirmation of that report.

New Jersey Sen. Cory Booker Ethan Miller/Getty Images News/Getty Images Booker is a strong supporter of marijuana rights. A year before introducing the Marijuana Justice Act in 2018, he proposed the Marijuana Reform Act, a slightly less comprehensive bill that would have nevertheless ended the federal ban on marijuana. Booker has often spoken out against the war on drugs and supported several smaller pieces of pro-marijuana legislation in the past.

Massachusetts Sen. Elizabeth Warren Mario Tama/Getty Images News/Getty Images In 2013, Warren criticized an opponent who supported marijuana legalization. But she has evolved on the issue, and now supports legalization through the Marijuana Justice Act. Warren is also one of the lead co-sponsors of the STATES Act, and has supported legislation that would allow marijuana businesses to more easily conduct financial transactions even if the federal ban isn't repealed.

Hawaii Rep. Tulsi Gabbard Slaven Vlasic/Getty Images Entertainment/Getty Images The Hawaii congresswoman is a strong and consistent supporter of marijuana legalization. She's endorsed the House version of the Marijuana Justice Act and many other pieces of legislation that would remove barriers to researching, taxing, and accessing the drug.

Minnesota Sen. Amy Klobuchar Stephen Maturen/Getty Images News/Getty Images As Minnesota's attorney general, Klobuchar had a D rating from NORML, indicating a "hard on drugs" stance. According to Mashable, she's the only Senate Democrat running for president who doesn't support the Marijuana Justice Act. However, Klobuchar said in a statement in February that she supports the legalization of marijuana, and she's endorsed the STATES Act. During her time in the Senate, NORML upgraded Klobuchar's ranking from a D to a B.

New York Sen. Kirsten Gillibrand Scott Olson/Getty Images News/Getty Images During her time in the House of Representatives, Gillibrand voted against legislation to protect states that legalized marijuana from federal intervention. But she supported such legislation as a senator, and is now a forceful advocate for legalization. Gillibrand supports the Marijuana Justice Act and has spoken about the disproportionate effect that marijuana laws have on black and Latinx communities.

South Bend Mayor Pete Buttigieg YouTube / PBS NewsHour Unlike the lawmakers on this list, the mayor of South Bend, Indiana, hasn't had to vote on any marijuana-related bills, because he's not a lawmaker. However, his office reportedly told Mashable that he supports legalization.

Texas Rep. Julian Castro Stephen Maturen/Getty Images News/Getty Images Like Buttigieg, Castro isn't a lawmaker and lacks any voting record on marijuana. He hasn't said whether he supports full legalization, but has suggested that he believes it's a state issue and has spoken out against federal efforts to interfere with state legalization efforts. When Castro was secretary of housing and urban development, however, the agency published a memo clarifying that marijuana users are ineligible for federal housing assistance.

Miramar Mayor Wayne Messam Joe Raedle/Getty Images News/Getty Images Messam's position on marijuana is unclear, as his campaign website doesn't mention marijuana policy and he doesn't appear to have spoken publicly about where he stands on the issue. Bustle has reached out to his campaign for clarity on his position.

New York Entrepreneur Andrew Yang Drew Angerer/Getty Images News/Getty Images On his website, Yang says that while he'd prefer that people not smoke marijuana heavily, America's "criminalization of it seems stupid and racist," and that the government should "proceed with full legalization of marijuana and pardon those in jail for non-violent marijuana-related offenses."

Author And Motivational Speaker Marianne Williamson Araya Diaz/Getty Images Entertainment/Getty Images Although Williamson doesn't mention the issue on her website, she told the Boston Globe that she "wholeheartedly" supports legalizing marijuana, a position she's hinted at before on her Twitter account.

Ohio Rep. Tim Ryan Zach Gibson/Getty Images News/Getty Images In July 2018, Ryan wrote an op-ed for CNN in which he called for marijuana to be legalized in all 50 states, and endorsed Booker's Marijuana Justice Act.

Montana Gov. Steve Bullock KPAX-TV / YouTube Bullock supports legalizing medical marijuana, which his state did in 2004. According to Marijuana Moment, he opposed a 2012 effort to repeal the state's medical marijuana law, pledging to ensure that "those in legitimate medical need get the opportunity to get medical marijuana, and those that don't are precluded from doing so." Bullock has a B grade from NORML.