Most of the 20,000 U.S. troops requested by the Department of Homeland Security to round up and detain undocumented migrants are expected to be rejected by the Defense Department because of concerns that it could violate the law, according to a U.S. official.
In a May 9 memo, a top DHS official asked the Pentagon to approve the massive military footprint inside the U.S. to help law enforcement track, detain and transport migrants.
According to the memo, DHS wants 10,000 military personnel to help with transporting migrants, 3,500 personnel to track fugitives inside the U.S., 2,500 to help detain people for immigration, and 1,000 for administration purposes. Another 4,000 would be used for various missions, including searching for unaccompanied migrant children in “remote or hostile terrain.”

Secretary of Defense Pete Hegseth testifies during a Senate Committee on Appropriations subcommittee hearing to examine proposed budget estimates for fiscal year 2026 for the Department of Defense, on Capitol Hill, June 11, 2025, in Washington.
Rod Lamkey/AP
Such a move is widely seen by legal experts as in violation of Posse Comitatus, the 1878 law that prohibits a president from using troops for law enforcement purposes.
When asked for comment, a Defense Department spokesperson said the request remains under review.
–ABC News’ Anne Flaherty