If you thought the Republican tax plan was just about huge tax cuts for the wealthy, think again. It’s also a major attack on science.

To understand why, let’s step back a bit. The scientific enterprise in America heavily relies on grad students. They do mostly invisible work in thousands of labs and research institutions across the US, on everything from basic research about human cells to clinical research on how to cure cancer. Their contributions are essential to running studies.

In exchange for that labor during their training, the federal government gives them a break on their taxes.

Very simply, grad students get their tuition and other school fees waived while they’re teaching or researching. When tax season rolls around, they’re exempted from having to pay taxes on that money (which never hits their pockets).

But under the House version of the tax bill, these waivers would become taxable income. “This means that MIT graduate students would be responsible for paying taxes on an $80,000 annual salary, when we actually earn $33,000 a year,” explained one MIT grad student, Erin Rousseau, in an op-ed in the New York Times. “That’s an increase of our tax burden by at least $10,000 annually.”

This waiver repeal appears in the House bill, not the Senate bill, and Congress is currently reconciling these two versions as part of its effort to form the tax code. But if this change becomes law, make no mistake: It’ll seriously damage the model that keeps America’s scientific labs running, wrote Jeremy Berg, the editor-in-chief of the Science journal, in another new op-ed.

The House bill would also drop the student loan interest deduction, which helps people who are paying their student loans manage their debt. And provisions in both the House and Senate bills would add an excise tax on income from university endowments.

“Disturbingly, these provisions emerged from a remarkably opaque process with little or no discussion of their policy objectives or analysis of data that would inform these important decisions,” Berg wrote. And they would hamper universities’ abilities to attract and retain the talent needed to run the labs that have made America a global scientific powerhouse.

That’s why groups as diverse as the American Association for the Advancement of Science and Society for Neuroscience are speaking out against the provisions and urging researchers to contact Congress to complain, and why students have been staging walkouts across the country.

“By making advanced education less affordable, it is likely to drive some students away from seeking higher education,” wrote AAAS and 67 scientific and engineering societies in a December 7 letter to members of the tax bill conference committee. Repealing provisions that help graduate students study “means that we will be shutting the door on new opportunities for discovery, exploration and innovation.”

Why are Republicans in Congress targeting grad students?

GOP lawmakers appear to have come up with the various tax cuts that impact grad students as a way to generate revenue to recoup losses from all the corporate tax cuts their plans contain. But if these provisions become law, critics expect they’ll make it harder for US universities to attract American students, and more difficult for all but the wealthiest among us to pursue advanced degrees.

Ted Yoo, a PhD student in chemical engineering at the University of California Irvine department of Chemical Engineering and Materials Science, explained how losing the waiver would dramatically change the contract between grad students and universities.

“To me, grad school was the promise that I would be able to dedicate myself to solving problems in peace. This was historically the idea behind the PhD system in the US, and it’s why we do actual research as part of our schooling,” he said. “Many argue this is exactly why America became such a scientific powerhouse. Repealing tuition remission would tear this up by the roots.”

If the waiver is repealed, he estimates he’ll be on the hook for some $3,000 per year in extra taxes, which would mean he can no longer afford his modest apartment near the university and he’ll have to move back in with his parents, adding a two-hour commute to his day. “The alternative would be to live out of a van, which I am seriously considering,” he said.