Democratic nominee Hillary Clinton and Republican nominee Donald Trump will have their first of three debates on Monday. One topic that likely won't be part of the debate, as was generally the case during primary season, will be the legalization or the decriminalization of marijuana.

As voters have shifted opinions on marijuana in recent years, so have government officials, as well as the leading presidential candidates. However, Clinton appears to a more specific stance on marijuana than Trump, and doesn't view it with much stigmatization.

Clinton has repeatedly stated that she wants to move marijuana from a Schedule I drug to a Schedule II drug, under the Controlled Substances Act, to increase research, as well as to stop imprisoning marijuana users. When asked in a town hall what she would do to decriminalize marijuana, Clinton said that she "will do a lot."

"I have no doubt there are very real benefits for people," Clinton said of marijuana in a town hall in February. 

Maya Harris, Clinton's policy adviser, said Clinton "will also ensure Colorado, and other states that have enacted marijuana laws, can continue to serve as laboratories of democracy."

Trump has offered a more cautious opinion on marijuana. He has stated that medical marijuana is something "we should really consider strongly," but legalization should be left up to the states.

Trump also questioned the effectiveness of marijuana legalization in Colorado. "It's not exactly going trouble free," Trump said at a rally. He also went as far as to say marijuana could have a negative impact on "" target="_blank">people's health and brain powers."

His campaign has also implied some reservations about marijuana use during the Republican primary season. In a Trump attack advertisement against Republican candidate Jeb Bush, there is a soundbite of Bush saying, "So 40 years ago, I smoked marijuana," which was followed by words on the screen that read: "Are we sure it was only forty years ago?"

Trump has stated that he never touches drugs, alcohol, tobacco or coffee. Clinton has said she hasn't smoked marijuana.