A federal district judge has blocked the state of Colorado from enforcing a key piece of Amendment 71, a voter-approved ballot measure that makes it significantly harder to change the state constitution.

In his court order, issued Tuesday morning, Judge William J. Martinez struck down the new petition requirements of Amendment 71 — also known as “Raise the Bar” — as unconstitutional, saying they violate the principle of “one person, one vote.”

The order could have major implications for the 2018 ballot, with advocacy groups pushing constitutional amendments on education funding, redistricting and taxes. The Colorado secretary of state’s office plans to appeal the ruling and to request that the order be stayed while the case is heard — a move that could keep the tougher requirements in play for the November election.

Passed overwhelmingly by voters in November 2016, “Raise the Bar” required the petitioning groups to put a constitutional amendment onto the ballot to gather signatures from 2 percent of registered voters in all 35 state Senate districts. Previously, getting a constitutional change on the ballot had no geographic signature requirements.

But shortly after the stricter requirements were approved, opponents such as Coalition for Colorado Universal Health Care and ColoradoCareYes filed suit, arguing that while Colorado’s 35 Senate districts were designed to be roughly equal in population, they don’t have the same numbers of registered voters. Senate District 23, for instance, had 51,723 more registered voters at the start of 2017 than District 21, according to the lawsuit — a gap of 60 percent.

That wide variance in Senate district voting populations creates “a classic vote-dilution problem, demanding strict scrutiny under the Equal Protection Clause,” Martinez wrote in the order.

Supporters of “Raise the Bar” say the change was needed, arguing that it should be harder to revise the state constitution, which critics say has become one of the longest and most convoluted in the nation. And, they argued, the existing process effectively shut rural communities out of the process, because signature gatherers typically target the state’s population centers along the Front Range.

“We submitted a number of affidavits from people in the rural communities who say they’ve never been asked to sign (a petition),” Suzanne Staiert, the deputy secretary of state, told The Denver Post in an interview. “They don’t feel they have a voice, … and now this court has taken away their voice again.”

Kate Roberts, the manager of the Amendment 71 campaign, ripped the decision, characterizing it as “a lone federal judge deploying what can only be described as a tortured logic in questioning the constitutionality of a constitutional amendment that requires those trying to amend the constitution to collect signatures in places other than Denver and Boulder.”

Roberts added: “Are the supporters of Raise the Bar confident that the 10th Circuit will overturn this judge’s wildly off-the-mark decision? We absolutely are.”

Tuesday’s ruling was a major victory for opponents of Amendment 71, which included a broad coalition of advocacy groups across the political spectrum that argued the new signature threshold would shut out all but the wealthiest causes from accessing the ballot.

Still, Lisa Weil, the executive director of Great Education Colorado, said her organization will continue to operate under Amendment 71 because of concerns about it being reinstated on appeal. Her organization is supporting Initiative 93 to increase the income tax on higher earners to generate another $1 billion for education spending by fiscal year 2020.

“We are going to continue to gather signatures in all 35 Senate districts,” she said Tuesday after the court’s ruling. “That is the prudent thing to do because of the probable appeal. We also think it’s also really important to engage communities throughout the state, so we are going to keep doing what we are doing.”

Amendment 71 also lifted the threshold for passage of constitutional amendments to 55 percent of the vote from a simple majority. The higher threshold remains intact with Tuesday’s court order.