THE WHITE HOUSE budget outline, released last week, opens a new front in Republicans' long-running war on science - and on scientists who insist on making decisions based on careful evaluation of empirical evidence.

America has been the world leader in investing in scientific research for decades, but the "America First" budget signals a major change, proposing to slash funding for research into curing or preventing diseases and epidemics, improving environmental and worker safety and preventing the worst effects of climate change.

It includes deep cuts in several science-based government agencies that have funded major breakthrough research. Many also have unearthed truths that are inconvenient to some industries.

Since the first Earth Day in 1970 to 2015, the Environmental Protection Agency has helped to reduce national emissions of such pollutants as lead, carbon monoxide and nitrogen dioxide by an average of 70 percent, saving hundreds of thousands of lives each year. The Trump administration wants to eviscerate the EPA, proposing to slash its budget by 31 percent.

The White House budget would cut the National Institutes of Health by 18 percent, a move that - if it were to go into effect - would have ramifications well beyond government. A significant percentage of its budget is awarded each year in highly competitive grants to about 300,000 researchers tackling such diseases as cancer, Alzheimer's and diabetes, as well as the traumatic brain injuries suffered by soldiers in Iraq and Afghanistan. (With this budget, you can forget Joe Biden's "cancer moonshot" and the notion that America will be first to find a cure.)

Scientists are particularly alarmed by a proposal to eliminate the Fogarty International Center, through which the NIH funds about 400 research and training projects around the world geared toward finding the most effective ways to control such epidemics as Ebola.

Other cuts would affect the Department of Energy's Office of Science, which has funded research into renewable energy and the power grid, NASA earth science projects, research by the National Oceanic and Atmospheric Administration, among many other agencies.

Taken together, the cuts would be "crippling to much of the federal science apparatus," Matt Hourihan of the American Association for the Advancement of Science told Vox.com. This is no mistake: If you're Donald Trump or the Republican party, science and scientists are dangerous to your worldview.

It is highly unusual to find scientists organizing a march, but these are highly unusual times. Even before the White House budget, thousands of scientists and their supporters had committed to publicly stand up for scientific integrity, planning a first-ever March for Science on Earth Day, April 22, in Washington - and 382 sites around the nation, including Philadelphia. At least 100 organizations have now endorsed the march, says Science Magazine, and hundreds of thousands of people have said they will attend.

Scientists used to believe that if they just provided the data dispassionately, politicians would make decisions based on fact, not ideology.

The evidence says otherwise, and it's conclusive.

What You Can Do: Join the March for Science on April 22. For more information and links to Philadelphia's march, at Penn's Landing from 10 a.m. to 2 p.m., see marchforscience.com.