The campaign to decriminalize marijuana overcame a historic congressional hurdle this week, but opponents and some supporters acknowledge the legislation faces serious obstacles.

The House Judiciary Committee on Wednesday voted 24-10 to approve the Marijuana Opportunity Reinvestment and Expungement Act, or MORE, which would remove marijuana from the federal list of controlled substances, where it's now banned alongside powerful drugs like heroin and LSD.

The bill would require federal courts to expunge convictions for marijuana offenses and authorize a 5 percent tax on marijuana sales to encourage minority communities to enter the cannabis business.

It's believed to be the first time a congressional committee has backed legislation to decriminalize marijuana at the federal level. Eleven states and Washington, D.C., have already done so.

But major roadblocks must be cleared before the measure can ever become law.

For one, the Judiciary Committee is only the first committee to have taken up the bill; it also has been introduced in seven other House committees, any or all of which could alter the debate.

And it isn't a lock to pass the Democratic-led House, because members are sharply divided over whether to try to push through sweeping legislation like the MORE Act or to go more slowly, emphasizing regulatory issues like the financial ramifications of decriminalization.

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Meanwhile, the measure is likely to be dead on arrival in the Republican-controlled Senate, opponents and even its primary sponsor suggested.

"This bill is nearly devoid of bipartisan support," Doug Collins of Georgia, the ranking Republican on the Judiciary Committee, said Wednesday.

Another Republican on the committee, Ken Buck of Colorado, said: "I don't think a majority of the Republicans will support this bill. It is even less likely that the Senate would take it up. Therefore, I would just suggest that we deal with other bills that we can get a much larger bipartisan support from."

The legislation's primary sponsor, Jerrold Nadler, D-N.Y., the committee's chairman, said he, too, assumed that the Senate wouldn't accept the bill "as is." But he said he didn't agree with the argument that "the Senate won't take this bill."

House Judiciary Committee Chairman Jerrold Nadler, center, speaks at a news conference with other Democratic representatives to highlight the Marijuana Opportunity Reinvestment and Expungement Act on Nov. 19, 2019. Olivier Douliery / AFP - Getty Images

"When the House passes a bill, it's part of a continuing process. It's not the end of a process," he said.

Should the bill ever make it through Congress, it must be signed by the president to become law.

President Donald Trump hasn't explicitly said whether he thinks the federal government should get out of the business of regulating marijuana. The closest he's come was in April, when he said he supported legislation that would protect legal marijuana activities in states that have approved them.

In a position paper, the White House says marijuana "has a high abuse potential and no approved therapeutic use," listing child developmental impacts, mental health problems and marijuana's potential as a gateway to addiction to harder drugs as reasons to pursue "substance use prevention" over legalization.