The acting Homeland Security secretary, Chad Wolf, is exercising authority under a 2005 law.
Department of Homeland Security - DHS
The request comes amid sharp divisions about the border wall between President Donald Trump and members of Congress.
Raul Rodriguez was not charged with a crime but he was fired by U.S. Customs and Border Protection.
Trump tweeted that McAleenan was leaving to spend more time with his family and go to the private sector.
Defense Secretary Mark Esper wrote the barriers will allow DoD to provide support to the Department of Homeland Security.
Gov. J.B. Pritzker's actions bring Miguel Perez Jr. one step closer to reuniting with his family.
The news comes as hurricane season is ramping up and Tropical Storm Dorian is heading toward Puerto Rico.
Internal Homeland Security emails and other documents show the issue set off a bitter clash within the department.
About 3,000 National Guard troops are posted around Louisiana with boats, high-water vehicles and helicopters.
ICE is not following its own deportment procedures, a new report finds.