Two Senate Republicans are pushing to extend stimulus checks in the next coronavirus relief package to almost 2 million Americans who were excluded from the initial round.

Sens. Marco Rubio (R-Fla.) and Thom Tillis (R-N.C.) want to ensure that U.S. citizens married to foreign nationals without Social Security numbers receive the same $1,200 direct payments that tens of millions of other Americans received earlier this year.

At the direction of the White House, that group of about 1.7 million Americans was excluded from the CARES Act that provided checks and payments, according to sources with knowledge of the March negotiations. The White House declined to comment.

Rubio, who introduced legislation in June along with Tillis to rectify the matter, is now fighting to include the measure in the forthcoming GOP coronavirus relief package.

"Senator Rubio believes that no American should be denied a federal stimulus check because they are married to someone who is not a U.S. citizen," a spokeswoman for Rubio said Thursday.

Their pitch is twofold: American citizens should not be excluded from government aid based on who they married, and Republicans should not be alienating any group of voters at a time when President Trump's poll numbers are dropping and the GOP is at risk of losing its Senate majority.

"The good news about this proposal is that it's a no brainer: Any GOP member not voting in favor is certainly going to be targeted as not being fair or equitable, and their motivations are going to be put in question," said Al Cardenas, co-chairman of the American Business Immigration Coalition and former chairman of the Florida GOP.

"For U.S. citizens to once again be treated in a disparate manner in trying times is mean-spirited, and there's no logic to it," he added.

Cardenas’s group as well as The Libre Initiative and the U.S. Conference of Catholic Bishops are appealing directly to Senate GOP leaders to include the proposal in the next coronavirus relief bill.

The proposal itself is a variation of a Democratic one that was shot down in earlier coronavirus bills.

The Democratic request would have sent relief checks to all taxpayers, including those who file taxes using an individual taxpayer identification number (ITIN).

Foreign nationals can opt to use an ITIN to file taxes in the United States for a variety of reasons, but one of the most common is that it allows undocumented immigrants, who are not eligible for Social Security numbers, to pay their taxes.

When the proposal was nixed by both the administration and GOP Senate negotiators, 1.7 million U.S. citizen spouses of ITIN holders were excluded from receiving stimulus checks.

The checks also weren’t sent to 9.9 million undocumented immigrants and 3.7 million U.S. citizen or legal permanent resident children of ITIN holders, according to a report by the Migration Policy Institute.

Their exclusion from the CARES Act, which provided the stimulus checks, caught many pro-immigration conservatives by surprise.

"I was hoping it was just an oversight," said Daniel Garza, executive director of The Libre Initiative, an influential Hispanic advocacy group within the political network funded by conservative megadonor Charles Koch.

"I'm just flabbergasted that this happened," Garza said.

"They need to redress it, fix it, never repeat it again," he added. "It's a question of flat-out fairness."

Excluding American citizens from economic relief over their marriages has opened a space for pro-immigration conservatives to speak out. And they’re pointing out the political dangers of excluding the same group in the next relief bill, particularly with so many living in battleground states.

In a letter to McConnell and Senate GOP leaders this past week, the American Business Immigration Coalition said Rubio’s bill would provide stimulus checks to 291,000 citizens in Texas, 81,000 in Florida, 31,000 in North Carolina, 16,000 in Wisconsin, 30,000 in Colorado and tens of thousands in other states.

Former Vice President Joe Biden is leading Trump in polls in Florida and even Texas, with suburban voters turning against the president's more hard-line measures on immigration and his administration’s handling of the pandemic.

Tillis is also facing a tough reelection bid in North Carolina.

"This is precisely the right moment to do it," Cardenas said of Rubio’s bill. "It's a key indicator in at least four states where the Senate races are up in the air, and nationally it's important for the party to show some unity."

Plus, some Republicans are eager to deliver a GOP victory on an issue where Senate Minority Leader Charles Schumer (D-N.Y.) has taken flak from the left.

The New York Immigrant Coalition on Tuesday hit Schumer with an ad campaign arguing he hadn't done enough to fight Republicans on assistance for ITIN holders, causing the state to lose out on more than $1 billion in stimulus checks.

But supporters of Rubio’s bill have to win over more than just Senate Republicans. Some fear immigration hard-liners such as White House adviser Stephen Miller could prevent the proposal from even being in the mix when negotiations start with Democrats.

Those same supporters acknowledge that if their proposal isn’t included in what’s likely to be the last COVID-19 relief bill before Election Day, it probably won’t ever find its way into law.

"If it's not gonna happen now, it's not gonna happen," said Cardenas.