In the federal spending deal passed by the House of Representatives Thursday, federal lawmakers attempted to block Washington, DC's marijuana legalization ballot initiative, which was backed by seven in ten voters. But advocates now say there are potential loopholes that will allow DC Council to implement the voter-approved initiative anyway.

Advocates, particularly the Drug Policy Alliance and the DC Cannabis Campaign, argue that the language in the congressional spending deal is ambiguous. And others say DC Council could use alternative sources of funding to pass the legalization initiative to Congress.

Some advocates say marijuana legalization is already enacted in DC

The spending deal says the DC government may not spend local or federal funds to "enact" a law, rule, or regulation that reduces penalties on marijuana. In theory, this should prevent DC Council from transmitting the voter-approved initiative to Congress for approval, as required by federal law, since it would take the city council's time and resources to do so.

Advocates argue DC voters already enacted the legalization initiative back in November. Under this argument, DC Council wouldn't be spending its time and resources to enact the initiative by sending it to Congress for a mandatory 30-day review period; it would be merely carrying out an initiative already enacted by voters.

Congresswoman Eleanor Norton, DC's nonvoting delegate to the House of Representatives, backed the idea in a recent statement. "DC's Initiative 71, it can be argued, was enacted when it was approved overwhelmingly by voters in November and was self-executing – i.e., it did not require enactment of any rules for its implementation," she said. "Therefore, it can be argued that the legalization of small amounts of marijuana can proceed."

But House Republicans' intent with the measure is very clear. The House Appropriations Committee's summary of the spending deal clearly states the bill "prohibits both federal and local funds from being used to implement a referendum legalizing recreational marijuana use in the District."

Dan Riffle, an attorney and marijuana legalization advocate, said congressional intent might not matter. "I agree it's clear," Riffle told me on Twitter, "but congressional intent only matters if we wind up in court (we won't), and court says language is vague."

DC Council could use reserve funds to transmit the initiative to Congress

The congressional spending deal prevents DC Council from using funds allocated for 2015 to transmit the legalization initiative to Congress. But DC Council could tap into reserve funds from previous years to pass the voter-approved initiative, according to the DC Appleseed Center for Law and Justice.

DC Appleseed Executive Director Walter Smith explained: "This is exactly what the District did last year during the federal shutdown when no funds were available to the District from the FY14 appropriation. As DC Appleseed recommended, the District used its reserve funds to keep the District government open, even though the federal government shut down. Significantly, then-Attorney General Irv Nathan confirmed the permissibility of this step in a legal opinion. And equally significant, Congress did not object to the District taking this step. That same step could be taken now with regard to Initiative 71."

Congress may try to sue to enforce its block on legalization

If DC Council were to implement the legalization initiative, it's unclear who would or could sue the local government to enforce the spending deal.

Riffle said the Department of Justice would have the legal standing to sue. But the Obama administration, which publicly opposes congressional attempts to block legalization in DC and asked federal prosecutors to let states experiment with legalization, might not be willing to do so. The Justice Department could also accept the argument that legalization was enacted in November.

If that proves to be the case, Congress could try to sue. But whether Congress has the ability to sue has always been a thorny legal issue. Courts have, for example, severely limited federal lawmakers' ability to file a lawsuit against the president.

David Rivkin, a constitutional litigator who served at the Department of Justice and the White House Counsel's Office under Presidents Ronald Reagan and George H.W. Bush, said Congress may have the ability to sue in this case. But he acknowledged the issue would be complicated by questions about whether Congress is being injured as an institution by DC's actions or whether there are any private plaintiffs that could show injury and step in.

"The situation here is complicated by the fact that, given DC's unique status — with Congress having delegated to DC certain authorities under the self-rule act — the action by the DC Council is not a constitutional violation; it is, essentially, a statutory violation, akin to a federal agency or department acting in violation of its statutory authority," Rivkin wrote in an email. "All in all, the possible congressional lawsuit against the DC Council would be more complicated than congressional challenges against the Obama administration's re-writes of the Affordable Care Act or Immigration and Naturalization Act."

DC Council may not take the risk

Despite the push from advocates, it's anyone's guess whether DC Council will attempt to defy the will of Congress and implement marijuana legalization this upcoming January. The DC attorney general's office is still reviewing the language of the spending deal, local radio station WAMU reported.

DC Mayor-elect Muriel Bowser suggested she could be willing to take the risk. "My job is to uphold the will of the voters, and the voters overwhelmingly support legalizing marijuana in the district," Bowser told the Washington Post.

It's possible the threat of congressional action outside of litigation, particularly restrictions on DC's budget, could prove too much for local leaders. Rivkin said the risk of more federally imposed budgetary restrictions could make a court less likely to intervene, since it indicates Congress can stop DC without judicial intervention.

Any potential loophole to the spending deal would only allow DC Council to implement the voter-approved initiative, which legalizes the possession, growing, and gifting of small amounts of pot. There's no question the spending deal would block any attempt by DC Council to implement the legal sales of marijuana, since that would cost money and Congress can place budgetary restrictions on that.

Read more: 6 questions about Washington, DC, statehood you were too disenfranchised to ask.