Republicans quietly added a provision to their tax bill that would hurt millions of children whose parents are undocumented

    House Republicans unveiled their tax reform plan on Thursday, which includes a modest expansion of the child tax credit. But under the proposal, undocumented immigrants will no longer be eligible for the tax credit, potentially depriving millions of children of the benefit.

A little-noticed provision in the GOP’s sweeping tax overhaul plan, which was released on Thursday, would make undocumented immigrant parents ineligible for the federal child tax credit.

As the law stands now, undocumented parents can receive a federal income tax credit up to $1,000 annually for each child, the vast majority of whom are American citizens.

The change could affect the more than 4 million US citizen children under 18 who live with at least one undocumented parent, as well as the approximately 1 million more so-called “dreamers” who were brought the US by their parents as children and remain undocumented.

Democrats, liberal advocacy groups, and immigrants’ rights activists have long been opposed to the idea, which has been repeatedly proposed by Republican lawmakers in recent years. Attorney General Jeff Sessions, a former senator from Alabama, and other conservatives attempted to pass this provision, known as the Child Tax Credit Integrity Preservation Act, on several occasions as an amendment to the tax code, arguing that it would save $4.2 billion in federal money going to undocumented families.

Melissa Boteach, a vice president at the liberal think tank Center for American Progress, told Business Insider that the provision amounts to an “attack” on children “to pay for tax breaks for the wealthy and corporations.”

She noted that there is strong research that indicates that the extra income the tax credit gives to low-income families has significant long-term benefits for the children, improving their educational, health, and career outcomes, on top of helping to mitigate immediate hardship.

Particularly for low-income families, the child tax credit can be key to staying out of poverty.

“It is a significant amount of income for a low-income family … losing that will definitely affect families,” Elaine Maag, a senior research associate at the non-partisan Tax Policy Center, told Business Insider.

Boteach said that while she didn’t expect the provision to be part of the bill, she wasn’t surprised that the proposal has been resurrected.

“This is not a new idea, it was not a surprise,” she said. “It’s still sad because you’re trying to market this bill as something that’s going to help families, using the child tax credit as a fig leaf, and even within the fig leaf you’re hurting children.”