Evidence emerged Monday, as Republicans celebrated the Senate’s passage of the Tax Cuts and Jobs Act, that small changes were made in the Senate to the bill’s language, which would allow illegal aliens to continue to claim the child tax credit.

Preventing the use of this important credit by illegals was a priority for some of the Republican tax reform plan’s most ardent supporters. Under existing law, one does not need a Social Security Number (SSN) to claim the benefit but can substitute an Individual Taxpayer Identification Number (ITIN), as illegal aliens frequently do.

Rep. Luke Messer (R-IN) made sure that a fix to this long-standing discrepancy was included in the House version of the tax bill. When the bill came out of chairman Kevin Brady’s (R-TX) House Ways and Means Committee, it included the language Messer originally inserted, demanding a credit claimant include “the taxpayer’s Social Security number on the return of tax for such taxable year.” This language would have blocked illegal aliens, who lack real SSNs, from claiming the lucrative benefit.

Yet when the Senate marked up the bill, the language was tweaked to allow some illegals to continue to claim the benefit. The text of the version the Senate eventually passed reads, “No credit shall be allowed under this section to a taxpayer with respect to any qualifying child unless the taxpayer includes the name and Social Security number of such qualifying child on the return of tax for the taxable year” (emphasis added).

The difference is not mere semantics. Many illegal aliens have children with SSNs. This includes the U.S.-born children of illegals, commonly known as “anchor babies,” alien children who have U.S. permanent residency, and so-called “Dreamers,” who, while themselves illegal aliens, have SSNs due to former President Barack Obama’s “Deferred Action for Childhood Arrivals” (DACA) executive amnesty scheme.

Who exactly is responsible for the change is unclear. Multiple House sources were adamant that the change was conceived entirely on the Senate side. At least one pro-amnesty Republican, Sen. Jeff Flake (R-AZ), was at the bargaining table demanding concessions for illegal aliens as a condition of supporting the tax cut bill, but there is no indication the change in child tax credit language was a concession he or those of similar inclination extracted.

Those in the House Republican majority who acted to fix the child tax credit in the first place expressed a willingness to oppose the Senate’s alterations in the upcoming conference on the bill. “The House bill requires a SSN in order to claim the child tax credit. Members will work to address this in conference to protect against fraud in this credit,” a Ways and Means spokesperson told Breitbart News.

“We can’t continue to reward people who come to our country illegally while those who work hard and play by the rules struggle to get ahead,” Messer, the author of the original language, told Breitbart New. “I was encouraged when President Trump included our legislation in his budget request to Congress, and I’m working to get it included in the final tax cut plan.”

The child tax credit is an important tax break for middle and working class Americans and is unavailable to individual filers who make more than $75,000 or married filers earning more than $110,000 a year.

The Personal Responsibility and Work Opportunity Act of 1996 (PRWOA) expressly provides that illegal aliens are “not eligible for any Federal public benefit.” But as Jan Ting of the Center for Immigration Studies (CIS) has explained at length, this benefit has continued to be available to illegals because the IRS has interpreted the ambiguity of the language of the current tax code to make no distinction between U.S. citizens and legal residents and claimants who have no right to be in the United States. A 2011 Treasury Inspector General for Tax Administration report suggests credits like these are putting billions of dollars in the hands of illegals. It was this situation that led to Messer and others attempting to fix the loophole.

CIS’s Ting, a law professor, sounded the alarm Monday that the Senate version had stepped drastically away from the House intent to keep the child tax credit from illegal aliens. Asked by Breitbart News if there was any plausible motive in the Senate’s change in language other than to benefit illegal aliens, Ting replied, “It’s a mystery to me. Why should we funnel taxpayer dollars to illegal aliens?”

Notably, even the Senate version’s language is an improvement to the existing law in keeping federal benefits from illegals. Under the altered version, at least illegal aliens with illegal alien children who are not covered by DACA will be unable to claim the child tax credit.