- Marijuana is "widely available" in Massachusetts due to decriminalization but there's little regulation of the drug, Sen. Elizabeth Warren said Thursday, explaining why she is open to supporting legalization.

"Massachusetts is in a very difficult position, because we have decriminalized marijuana, but that means it's fairly widely available," Warren said, referring to the 2008 ballot initiative that decriminalized small amounts of marijuana in Massachusetts. "But there's no real regulation of it."

Warren, D-Cambridge, added: "And I think what we really need is to have some regulation of it, and that means I would be open to the possibility of legalizing marijuana in Massachusetts."

Question 4, an initiative on the November 2016 ballot, seeks to legalize marijuana for recreational use and set up a Cannabis Control Commission to regulate the substance.

Supporters say the move would bring tax revenue into state coffers and drive down a black market. But opponents, including Gov. Charlie Baker and Boston Mayor Marty Walsh, say legalizing the drug would put people on a path to harder substances.

Pressed on whether she would vote "yes" on the ballot question, Warren said, "What I just said is that I would be open to it because I think that the problem we've got right now in Massachusetts is that we've decriminalized it which makes marijuana available but there's no regulation over it for safety."

Warren said Massachusetts should learn from other states that have legalized marijuana. Twenty-five states and the District of Columbia have legalized marijuana in some form.

Four states have legalized it for recreational use: Colorado, Washington, Alaska and Oregon.

Marijuana being accessible in all those states "yet we can't even do serious medical research because of the way the federal government classifies marijuana," Warren said.

Marijuana is classified a Schedule 1 drug, meaning the Drug Enforcement Administration believes it has "no currently accepted medical use and a high potential for abuse," according to the agency's website.

"I think that just makes no sense at all," Warren said. "And so I've been pushing back against this. I think what we need is an opportunity to study the drug better and we also need better regulation for it."