Both groups, as well as Republican leaders, say U.S. District Judge Susan Bolton made a mistake when she ruled that federal law allows people without proof of citizenship to vote in the presidential election. Bolton said as long as voters use the federal form – which does not require proof of citizenship – they can vote in federal elections.

But the battle before the 9th Circuit Court of Appeals is about more than just the provisions of the National Voter Registration Act.

Republicans calling for an emergency decree believe that barring 19,439 Arizonans from voting for president would help the Republican candidate. That's how many voters are currently registered in Arizona using the federal form in question.

Only 14.3 percent of those in Arizona who filled out the federal form — and who are only allowed to vote in federal elections — are registered Republicans, said attorney Thomas Basile, who represents the GOP. In contrast, he told the appeals judges, Republicans make up 34.5 percent of all active registered voters in Arizona.

“The court-ordered inclusion of these individuals in the presidential election process inevitably undermines the relative competitive position of the Republican presidential candidate,” Basile said.

This difference could be crucial in 2024: Democrat Joe Biden defeated Republican Donald Trump in Arizona in 2020 by 10,457 votes, earning the state's 11 electoral votes.

There may be more at stake than just the presidential election.

Republicans at the state and federal levels, as well as Arizona House Speaker Ben Toma and Senate President Warren Petersen, acknowledge that the National Voter Registration Act allows users of the federal form to participate in congressional elections.

But they are challenging another part of Bolton's decision. It overturned a 2022 Arizona state law that says those using the federal form cannot vote for president, can only vote in person if they show proof of citizenship, and do not have the same convenience of voting from home that other registered voters are entitled to.

Unless the 9th Circuit Court of Appeals overturns the part of its ruling that says voters do not have to show up in person at the polls, those 19,439 federal-only voters will have the right to cast early ballots in the hotly contested race for the U.S. Senate and the state's nine seats in the U.S. House of Representatives.

“By overriding the Legislature's decision that 'federal electors only' cannot vote for Arizona's presidential electors or vote by mail, the injunction (issued by Bolton) distorts the competitive environment underlying the 2024 election in a way that is unfavorable to the Republican National Committee and Republican candidates,” Basile wrote.

Republicans will face fierce opposition – and not just from the voting rights groups that filed the original lawsuit against the provisions of the 2022 law.

Democratic Secretary of State Adrian Fontes will not comment officially on the dispute, said his lawyer Craig Morgan.

But Morgan is urging the appeals judges not to grant the emergency motion. Simply put, he said, it is simply too late to make changes to the way this year's election is run.

“Election officials across Arizona are preparing for what is expected to be a very active election cycle in 2024,” he wrote in court documents.

“Last-minute state policy changes such as those requested in the motion can (and Secretary Fontes believes) have a drastic impact on how affected votes are collected and processed,” Morgan said. “Such confusion and chaos just before an election will undoubtedly raise doubts among voters about our voting procedures, our election officials, and our elections themselves.”

The measure in question is specifically based on claims by Trump supporters, who, however, provide no evidence that people who are not in this country legally went to the polls and cast their votes.

Senator Jake Hoffman (R-Queen Creek) said one reason for this may be that about 21,000 Arizona residents registered to vote in 2020 without using the state registration form, which requires proof of citizenship.

Instead, they registered using the federal form created by the Election Assistance Commission, which entitles registrants to vote only in presidential and congressional elections. Proof of citizenship is not required, but applicants must sign an affidavit declaring – under penalty of perjury – that they are indeed citizens.

Hoffman argued that this “ignores the Constitution.” He said Congress may only pass laws regulating the time, place, and manner of election of Representatives and Senators.

“The Constitution does not give Congress such power over presidential elections,” Hoffman said at the time, saying that power is reserved for the states. He said that means Arizona is free to set the voting requirements for presidential elections, including proof of citizenship.

In signing the bill, then-Republican Gov. Doug Ducey said he accepted Hoffman's argument that there was a “legal nuance” that allowed the state to require proof of citizenship in presidential elections that it could not require in congressional elections. He said it was also the right thing to do.

“I believe that voter ID is the first step to being able to vote and therefore proof of citizenship,” Ducey said at the time. “This law ensures that.”

Bolton disagreed in her original decision.

“The plain language of the National Voter Registration Act reflects the intent to regulate all elections for federal office, including elections for president or vice president,” the judge wrote last year in barring the state from enforcing the provisions while the case is heard in federal court. “And binding precedent shows that Congress has the power to control registration for presidential elections.”

Bolton also said federal law overrides the challenged law's requirement that anyone using the federal form must provide documented proof of citizenship in order to vote by mail in each election for which they are eligible to vote. She said that's not what federal law says.

“Congress has recorded that it passed the National Voter Registration Act not only to establish procedures to increase the number of eligible citizens who register to vote in federal elections, but also to enable federal, state, and local governments to implement this chapter in a manner that increases the participation of eligible citizens in federal elections,” Bolton said.

“In addition, Congress found that discriminatory and unfair registration laws and practices have a direct and harmful impact on voter turnout in elections for federal office and can disproportionately affect the turnout of various groups, including racial minorities,” the judge continued. “It is the duty of federal, state, and local governments to promote the exercise of the fundamental right to vote.”