With primary season officially kicking off, we thought we'd check in with the three main candidates for the Democratic Party presidential nomination to see where they stand on cannabis.

Here they are, ranked by their grades from the Marijuana Policy Project.

1. Bernie Sanders, A

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The Vermont senator is far ahead of the pack when it comes to legalization. And the candidate close behind isn't a Democrat - it's Republican presidential candidate Senator Rand Paul.

Bernie has called for an end to the War on Drugs, decried the racial injustice behind cannabis prohibition, and introduced a bill that would repeal federal prohibition and allow states to legalize, regulate and tax marijuana like alcohol and tobacco.

Here's his freshest take on the endemic injustices in the American legal system:

"We have a criminal justice system that is broken," Sanders said during the Jan. 17 Democratic presidential debate. "Who in America is satisfied that we have more people in jail than any country on earth, including China - disproportionately African-American and Latino. Who is satisfied that 51 percent of African-American young people are either unemployed or under-employed? Who is satisfied that millions of people have police records for possessing marijuana when the CEOs of Wall Street companies who destroyed our economy have no police records? We need to take a very hard look at our criminal justice system, investing in jobs and education - not in jails and incarceration."

For these reasons, the Marijuana Policy Project gave Sanders the highest grade among all presidential candidates.

But not everyone is onside with Sanders record on cannabis reform. Check out John Hudak's analysis of Sanders' failure to build support for his efforts.

2. Hillary Clinton, B

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The former secretary of state still leads the pack in national polls. But she trails Sanders when it comes to taking a progressive stance on cannabis.

During an interview with Joe Mathieu of WBZ on Jan. 25, Clinton reaffirmed the three planks of her position on cannabis reform: she promises to respect each state's right to legalize, monitor the situation in those states, and move cannabis from a Schedule I to a Schedule II drug so that it can be researched more thoroughly as medicine.

"I think that states are the laboratories of democracy, and four states have already taken action to legalize, and it will be important that other states and the federal government take account of how that's being done, what we learn from what they're doing. And I do think on the federal level we need to move marijuana from the Schedule I of drugs, move it to Schedule II, which will permit it to be the basis for medical research. And a lot of experts in the field are telling me we've got to learn a lot more. For example, you're taking marijuana for medical purposes, how does it interact with all the other drugs you're taking? What should be the right dosage? And different states have adopted different approaches to medical marijuana. And if we move toward legalization, what are the consequences? Let's learn so that we are smart about this."

Her stance has left commentators like Ben Adlin of Leafly feeling underwhelmed by Clinton's "safe, mealy-mouthed responses about an issue on the verge of massive change." Indeed, Republican Rand Paul's stance is arguably more progressive than Clinton's, while Donald Trump, Ted Cruz, Jeb Bush and others have similarly pledged to respect each state's right to legalize.

On cannabis, Clinton seems more interested in blending in with the crowd rather than standing out.

3. Martin O'Malley, B- (campaign suspended)

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Like Clinton, the former governor of Maryland has called to reclassify cannabis as a Schedule II instead of a Schedule I drug. Like Clinton, O'Malley is leery of legalization, but he wants to let states experiment with legal cannabis so that legislators can decide how to proceed on the issue:

"I think we need to have an open mind about that [legalization]," he told CNN in October 2015. "I think there's a lot we can learn from Colorado and Washington State. They seem to be keeping very good records. They understand they are the first in the nation, and I think we should be guided by [why] what they are doing in Colorado increases harm or reduces harm."

But unlike Clinton, he has also supported decriminalization - at least in the state of Maryland. When agreeing to sign the state legislature's decriminalization bill in April 2014, then Governor O'Malley released the following statement:

"As a young prosecutor, I once thought that decriminalizing the possession of marijuana might undermine the public will necessary to combat drug violence and improve public safety. I now think that [it] is an acknowledgment of the low priority that our courts, our prosecutors, our police and the vast majority of citizens already attach to this transgression of public order and public health."

He also agreed to appear in a Fear and Loathing in Las Vegas spoof. So unless Bernie and Hillary agree to do a Cheech and Chong sketch, O'Malley will be the most progressive candidate to parody cannabis culture:

h/t CNN, NBC News, WBZ, Leafly, Washington Post, CNS News