Lawmakers, scientists, and advocacy groups are decrying President Donald Trump's proposed cuts to the National Institutes of Health (NIH), saying they represent another broken campaign promise and a "heartless" attack on critical medical research.

In keeping with his war on science, Trump's "skinny budget" released earlier this month outlined a 20 percent cut to the NIH; a specific proposal put forth this week would cut an additional $1.23 billion from the agency's 2017 fiscal year budget. The reduction is part of $18 billion in cuts Trump is requesting "from medical research, education, and other programs for the remainder of the current fiscal year to finance construction of a border wall and build up the military," as Bloomberg reported.

According to STAT:

[T]he NIH cuts would wipe $50 million from funding for IDeA grants, which are intended to help spread biomedical research geographically across the United States. The rest, nearly $1.2 billion, would more broadly reduce research grant funding. The Trump administration is also proposing a $314 million cut at the Centers for Disease Control and Prevention through reductions to occupational safety and public health preparedness grants, as well as domestic and global HIV/AIDS programs. The mental health block grants administered by the Substance Abuse and Mental Health Services Administration would also be cut by $100 million under the White House proposal.

Health and Human Services Secretary Tom Price defended the proposed cuts before a House committee on Wednesday. But slashing medical research will be a hard sell, both in Congress and to the public. A Quinnapiac poll released last week found overwhelming opposition to cutting medical research, with 87 percent disapproval and only 10 percent of respondents voicing approval.

Meanwhile, organizations representing a variety of scientific and public health interests decried the latest proposal.

"The president continues to put the health and well-being of Americans in danger to move forward a so-called 'hard power budget,' even while leaders from his own party view investments in biomedical research as critical to the nation’s security," said Benjamin Corb, director of public affairs for the American Society for Biochemistry and Molecular Biology. He said implementing the NIH cuts would amount to "throwing progress out the window."

Similarly, the group UsAgainstAlzheimer's said the recent proposals "represent an assault on the hopes of millions with Alzheimer's and related dementias who are desperate for a cure." Trump, whose father had Alzheimer's, once called the disease a "total top priority for me."

Others chimed in online:

$300 million in cuts by Trump admin would set us back in the fight to achieve an AIDS-free generation. https://t.co/ac23a2QCMy SCROLL TO CONTINUE WITH CONTENT Never Miss a Beat. Get our best delivered to your inbox.





— Chad Griffin (@ChadHGriffin) March 29, 2017

Now is the time to be investing in medical research. The budget cuts proposed by President Trump to NIH will have devastating effects. — Rep. Val Demings (@RepValDemings) March 29, 2017

More info on proposed cuts to #NIH (funds scientists like me). It targets states that already receive low funding: https://t.co/YeWaOJmGPq pic.twitter.com/OaQ4wzBZ00 — Ian McLaughlin (@_Anthropoid) March 28, 2017

We need Congress to know #NoCutsForCancer! Call your lawmaker NOW & let them to reject more cuts to @NIH https://t.co/EruQw6IIIi pic.twitter.com/7zkcfWwvBX — ACS_SouthDakota (@ACS_SouthDakota) March 29, 2017

Exactly the cost of the first 62 miles of the border wall. Believe me NIH is much more likely to save your life than is Trump's wall. https://t.co/RyaaZQkI2m — Jonathan Reiner (@JReinerMD) March 29, 2017

NBC News laid out how other health and science programs across government agencies are targeted under Trump's latest proposal:

Take $350 million from the National Science Foundation's $6.9 billion budget

Cut $37 million from the Department of Energy's $5.3 billion worth of science programs

Excise $48 million from the Environmental Protection Agency's research and development budget of $483 million

Cut in half the $101 million Teen Pregnancy Prevention program

Reduce Food and Drug Administration staff spending by $40 million

Cut domestic and global HIV/AIDS programs by $100 million plus cut the Presidential Emergency Program for AIDS Relief (PEPFAR) $4.3 billion budget by $242 million

Completely delete the $72 million Global Health Security fund at the State Department and cut other global health programs by $90 million and $62 million for global family planning

NBC quoted Charles Kieffer, Democratic staff director for the Senate Appropriations Committee, who told a panel at the Bipartisan Policy Center on Tuesday: "His focus is on cutting science programs."

And it has researchers terrified, as Washington University in St. Louis assistant professor of genetics Mike White wrote Wednesday:

No wonder Trump's budget has so many scientists on edge. To see how these cuts would play out in individual labs, I asked some of my scientific colleagues how they would be affected if cuts made it almost impossible to get an NIH grant next year. Younger scientists with new university positions, even those with money from private foundations but no NIH grant, all told a similar story: "lab closed, research over, trainees gone." Scientists who are just finishing their training are rethinking a career in research, asking themselves, "Should I quit now?" Some established scientists, with a record of years of successful science, have expiring grants; to keep their labs open, they need to obtain new grants in the next year or so. "To say I am concerned about this would be an understatement," an established University of Utah scientist told me. [...] The cumulative effect of thousands of stories like these would last for years as scientists scaled back, labs closed, and people left their fields altogether. This potential effect cannot be easily reversed, especially since the cuts would hit younger scientists hard. If an incoming generation of researchers can't do their work, or even keep their jobs, America's leading role in science will inevitably be diminished. If that happens, more than prestige is at stake: Our economy will lag, and our nation’s health will suffer.

A March for Science is scheduled for April 22 in Washington, D.C., with sister marches planned around the country.