It's a rare moment in U.S. politics when Republicans and Democrats unite in opposition to the same government policy.

But the request from Donald Trump's new Presidential Advisory Commission on Election Integrity for states to turn over voter data to the federal government has triggered just that.

"They can go jump in the Gulf of Mexico," Mississippi Secretary of State Delbert Hosemann, a Republican, said in a statement. "And Mississippi is a great state to launch from."

Alison Lundergan Grimes, Kentucky's secretary of state, has been very vocal in her opposition to the commission's request for voter data. (John Sommers II/Reuters)

The Democratic response has been equally colourful.

"There's not enough bourbon here in Kentucky to make this request seem sensible," said Alison Lundergan Grimes, Kentucky's secretary of state.

'Just get the facts on the table'

The backlash started after Kris Kobach, the commission's second-in-command behind Vice-President Mike Pence, sent a letter to the states asking for a list of voter data including:

Full name, address and date of birth.

Political party affiliation.

Last four digits of social security number.

Voting history over the last decade.

Criminal record.

Whether the voter is registered in another state, is a member of the military or an overseas citizen.

The commission says it's simply trying to root out election fraud by looking for vulnerabilities in the voting process, and that it's only requesting information that's publicly available under state laws.

"Why not collect evidence and just get the facts on the table? That would be a good service to the American public. Period," Kobach said in an interview with NPR.

But officials from more than 40 states have pushed back, saying they won't hand over any or will only provide some of the data. They argue it's a federal intrusion on state rights, and many are concerned about the commission's motivation for asking for the information. Some also doubt the commission will protect the data properly.

Trump reacted in a tweet last Saturday, writing: "Numerous states are refusing to give information to the very distinguished voter fraud panel. What are they trying to hide?"

'Alternative election facts'

Trump's tweets are part of the problem.

A few weeks after the presidential election, he tweeted that he would have won the popular vote — in addition to his electoral college victory — if "you deduct the millions of people who voted illegally."

He made the widely debunked claim without presenting any evidence that large-scale voter fraud occurred, and none has yet been found.

"Studies show that voter fraud exists in the United States, but just barely," said David Becker, executive director of the Washington-based Center for Election Innovation and Research. "It's not zero, but it's not much more than zero."

Trump has said he would have won the popular vote, too, had it not been for the 'millions of people who voted illegally' in the 2016 presidential election — a claim experts and state officials say simply isn't supported by the facts. (Yuri Gripas/Reuters)

Critics say Trump is trying to use the commission to find proof to support his own allegation.

"At best, this commission was a pretext to validate Donald Trump's alternative election facts, and at worst, it's a tool to commit large-scale voter suppression," Virginia Gov. Terry McAuliffe, a Democrat, said in a statement.

'Voter rolls aren't up to date'

In response to such accusations, Kobach points out the federal government doesn't have the power to knock people off voter rolls.

But the commission's database could still result in people being unfairly prevented from voting, according to Chris Calabrese, a vice-president at the Center for Democracy and Technology.

He said the commission will likely compare the voter data with information on other government lists, such as those used to verify an individual's immigration status.

The commission could tell state officials that its analysis shows a particular individual isn't supposed to be on the voter roll.

This could happen, for example, if the commission's data comparison shows the person is registered to vote in two states.

The trouble with this approach, Calabrese says, is such lists are always in flux and out of date. The data is constantly changing for a variety of reasons, such as people becoming citizens, moving and dying, so there's plenty of room for error and mischief.

"What we've seen is an effort to say if you're not registered in the right place then you're attempting to commit fraud, even though there's no real evidence of that," he said. "The voter rolls aren't up to date, which isn't the same as someone trying to vote fraudulently."

Bully pulpit?

The commission's membership has also given critics ammunition.

Kobach, for example, was a member of the Trump transition team and has been described as a "voter fraud vigilante."

He spearheaded the passage of tougher voting measures in his home state of Kansas.

The SAFE Act requires voters to show a birth certificate, passport or naturalization papers to cast a ballot. The American Civil Liberties Union condemned the law as an attempt at voter suppression, arguing it discriminates against minorities and low-income residents.

Kobach is also running to be governor of Kansas, and he's gotten himself into some trouble for allegedly highlighting his commission role while out on the campaign trail. The Lawyers' Committee for Civil Rights Under Law has filed a formal complaint against him for allegedly violating the Hatch Act, which prohibits a federal employee from exploiting his position for electoral purposes.

U.S. Vice-President Mike Pence is leading the election integrity commission — a fact that has critics concerned the body has partisan goals. (Joe Skipper/Reuters)

And with Pence at the helm, there's added concern the commission is partisan.

"Not only is the project half-baked, it's pre-cooked," said Justin Levitt, a former deputy assistant attorney general at the Justice Department.

"If it's led by partisan elected officials, then it becomes a bully pulpit to press for legal change using massively inflated allegations that don't really follow the facts."

The 'wolf on the doorstep'

The commission, however, is pushing ahead despite the opposition.

"This is a process where we have to keep our eyes focused on the objective of protecting U.S. elections," commission member Ken Blackwell said on CNN Thursday.

But Becker of the Center for Election Innovation and Research argues the commission is focusing on the wrong issue.

After all, he says, there's no proof of widespread voter fraud in the last election, but there is a strong consensus that Russia interfered in it.

"The Trump White House seems singularly unconcerned about this major threat," he said.

"When you're spending federal taxpayer money chasing a wild goose when there's actually a wolf on your doorstep — that's not wise."