WASHINGTON ― House Speaker Mike Johnson (R-La.) has attached a bill aimed at keeping non-citizens from voting in federal elections to a must-pass government funding bill set for a vote this week.

It’s already illegal for non-citizens to vote in federal elections, but Republicans want to amplify former president Donald Trump’s lies that Democrats are using illegal voters to steal the 2024 election from him.

Johnson has been stoking voter fraud fears for months, insinuating in press conferences and news articles, without evidence, that millions of undocumented immigrants will steal the election from Trump.

“The threat is very real,” Johnson wrote last month in an opinion piece for Fox News, noting that noncitizens can walk into their local department of motor vehicles and fill out a registration form. “That noncitizen can then cast a ballot and help decide the direction of America.”

Available evidence suggests noncitizens generally don’t cast ballots, partly because voter registration forms warn it’s a crime to do so.

When Trump created a commission to investigate his own claims that as many as 5 million illegal ballots were cast in the 2016 election, investigators failed to find the fraud and the commission disbanded. Trump didn’t have any luck substantiating fraud claims from 2020 either, though he said on his website over the weekend that when he wins in November, “those people that CHEATED will be prosecuted to the fullest extent of the Law.”

According to the National Task Force on Election Crises, which calls itself a “cross-partisan” group of election, cybersecurity, voting rights and emergency response experts, states already have methods in place, like checks of Social Security, department of motor vehicle and other databases, to prevent undocumented immigrants from registering and voting.

“The number of noncitizens who have been proven to have registered to vote in federal elections in the United States is miniscule—and the number of noncitizens who have attempted to vote is an even smaller fraction of that number,” the group said on Aug. 29.

This week, the House will likely vote on a “continuing resolution” to fund government operations with a Republican bill that among other things would require states to get proof of citizenship before they register people to vote.

Members of the House Freedom Caucus, a hardline group of conservative and libertarian Republicans in the House, had lobbied for tying the citizen voter bill to the must-pass legislation during Congress’ summer break.

“This will be a test to see if Congress believes in preserving FREE and FAIR elections. This is THE HILL TO DIE ON,” Rep. Ralph Norman (R-S.C.) posted on social media Friday.

Trump, for his part, said Republicans should “shut down the government in a heartbeat” if the funding measure doesn’t include the Safeguard American Voter Eligibility Act, the Republican election bill. Trump’s lies about the outcome of the 2020 election, which he lost but claimed was subject to widespread fraud, motivated the Jan. 6, 2021, attack on the Capitol by his supporters.

While the prospect of a deadlock over the citizen voter issue could delay the bill to keep the government open after Sept. 30, in reality it is unlikely to block it. During his term, Trump urged Republicans on Capitol Hill to shut the government down several times only to cave before it actually came to that. Both parties would see a shutdown so close to the November presidential election as such an unpredictable political wild card it should be avoided.

If a shutdown did occur, it would be the latest in an election year since 1990, when there was a three-day shutdown that ended Oct. 9, according to Congressional Research Service data.

The House Rules Committee on Monday will meet to consider the guidelines for floor debate on the bill and what, if any, amendments to it may be voted on by House members.

Democrats will oppose the election fraud gambit.

“We will not let poison pills or Republican extremism put funding for critical programs at risk,” Senate Majority Leader Chuck Schumer (D-N.Y.) said Sunday in an open letter to his Democratic colleagues.

The White House said Monday President Joe Biden would veto the bill if it somehow made it to Biden’s desk.

“This legislation is unnecessary,” the White House Office of Management and Budget said in a formal statement. “It is already illegal for noncitizens to vote in Federal elections ― it is a Federal crime punishable by prison and fines.”

Some hardline conservatives won’t support the funding bill, either.

“I don’t care which bright shiny object is attached to it, or which fake fight we start and won’t finish,” Rep. Thomas Massie (R-Ky.) said Sunday on social media. “Congress is spending our country into oblivion, and this bill doesn’t cut spending.”

In his op-ed last month, Johnson referred to a 2014 study that he said suggested “6.4% of noncitizens in the U.S. had voted in the general election” in 2008. The paper has been controversial; its own lead author once lamented that “there has been a tendency to misread our results as proof of massive voter fraud, which we don’t think they are.”

In May, Johnson essentially admitted there’s no proof of widespread noncitizen voting, saying he knows “intuitively” it’s happening even though “it’s not been something that is easily provable.”