President Donald Trump says he will “temporarily suspend immigration” to the United States while the Chinese coronavirus crisis continues to claim American lives.

On Monday evening, Trump said he will pause all immigration to the U.S. — a moratorium that has not been enacted in four decades — while at least 22 million Americans are unemployed due to mandatory business closures by state governments.

“In light of the attack from the Invisible Enemy, as well as the need to protect the jobs of our GREAT American Citizens, I will be signing an Executive Order to temporarily suspend immigration into the United States,” Trump wrote on Twitter.

In light of the attack from the Invisible Enemy, as well as the need to protect the jobs of our GREAT American Citizens, I will be signing an Executive Order to temporarily suspend immigration into the United States! — Donald J. Trump (@realDonaldTrump) April 21, 2020

CBS News reports, according to sources, reports that the Trump administration has been working on the executive order for weeks:

This immigration executive order is real and the White House has been working on it for several weeks. It is not a blanket policy and includes exceptions, a source familiar tells @CBSNews’ @PaulaReidCBS. https://t.co/GPk3iAd0Qg — Camilo Montoya-Galvez (@camiloreports) April 21, 2020

Trump’s upcoming executive order to pause immigration to the U.S. is widely supported by American voters. An Ipsos poll released this month found that nearly eight-in-ten Americans, or about 79 percent, want a full halt on immigration to the U.S.

Likewise, the latest Pew Research Center survey reveals that more than 80 percent of American adults call mass migration to the U.S. a “threat.”

For weeks, Breitbart News has chronicled the historical precedent for an immigration moratorium during times of national crisis. During the Great Depression, for instance, mass unemployment was eased by major cuts to legal immigration levels that stayed below 100,000 annual admissions for nearly 15 years from 1931 and 1945.

Immigration Pause Would Come After Four Decades of Foreign Worker Inflow https://t.co/3oaYm5YObi — John Binder 👽 (@JxhnBinder) April 17, 2020

Since at least 1999, the U.S. legal immigration system has predominately delivered green cards to Mexican nationals, Chinese nationals, and Indian nationals. Over a single two-year period, 2000 and 2001 for example, the U.S. delivered green cards to more than 100,000 Chinese nationals.

From 2016 to 2018, the U.S. delivered green cards to nearly 220,000 Chinese nationals and more than 184,000 Indian nationals — the overwhelming majority of which join the U.S. workforce to compete for jobs against Americans.

Trump’s authority over immigration, like all other presidents, is vast and broad.

In June 2018, the U.S. Supreme Court reaffirmed the president’s control over legal immigration. In Trump v. Hawaii, the court stated that presidents have extraordinarily broad discretion to admit or exclude foreign nationals from the U.S. when they believe doing so is in the national interest.

John Binder is a reporter for Breitbart News. Follow him on Twitter at @JxhnBinder.