White House adviser Stephen Miller on Wednesday warned of a policy of “nationwide catch and release” if Democratic nominee Joe Biden is elected to the White House -- painting a stark contrast with the Trump administration’s stance on immigration.

Miller, who has played a key role in forming the administration’s immigration policy, ripped into Biden’s immigration plan in a call with reporters and described what she sees as a radical agenda that would flood the U.S. with illegal immigrants.

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"The Biden plan would implement nationwide catch and release for every nationality, 100 percent of people from 100 percent of countries will be released pending a court date,” he said. “Within a week of that happening there would be a rush on the border on a global scale.” 

He went on to predict catastrophe for the U.S. if Biden’s plan was implemented, warning of an “influx of low-wage workers [that] will drive down wages, deplete the middle class, bankrupt Social Security, Medicare, Medicaid, overcrowd every school in the middle of a pandemic.”

The Trump administration has taken a wide range of measures to end “catch and release” -- a process in which immigrants caught crossing the border were briefly detained, processed and then released into the interior to await their court date.

The administration claimed that such a process acted as a pull factor, bringing migrants north, and led to the 2019 border crisis. The administration took steps including making asylum cooperative agreements with Northern Triangle countries and expanding the Migrant Protection Protocols (MPP.)

MPP, known as the “Remain in Mexico” policy, keeps migrants in Mexico as they await their hearing, and officials have credited it as a “gamechanger” in bringing apprehensions and border traffic down.

Biden has said he will end a number of Trump-era policies including “Remain-in-Mexico” and will also end the travel restrictions to certain nations that has been called a “Muslim ban.” 

The former vice president has proposed other more liberal immigration measures too, including increasing the refugee cap, expanding a number of legal immigrant pathways, and imposing a moratorium on deportations.

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Biden has also criticized Trump’s handling of the border crisis, pointing to the “zero tolerance” policy that resulted in some children being separated from their parents.

"Their kids were ripped from their arms and separated," Biden said last week's presidential debate.

Miller on Wednesday pushed back against that criticism: “I will also make the point that Joe Biden will be the best friend that child smugglers and child traffickers has ever had in the White House.” 

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“His policies would incentivize child smuggling and child trafficking on an epic global global scale. It would reward some of the most evil criminal organizations in the world,” he added.

Fox News' Matt Leach contributed to this report.