A shakeup at the Department of Homeland Security is going far beyond the resignation of Secretary Kirstjen Nielsen, and White House senior adviser Stephen Miller is the driving force behind these dramatic changes. The White House fired the head of the Secret Service, Randolph "Tex" Alles, and DHS Undersecretary Claire Grady on Monday. Citizenship and Immigration Services director L. Francis Cissna is also expected to leave, along with the department's general counsel, John Mitnick.

The White House has been divided over immigration policies for weeks, with the president's building frustration colliding with existing law and court challenges, reports CBS News chief Washington correspondent Major Garrett. It all came to a boiling point late last month, when the president abandoned any bridge-building and sought confrontation — in his own administration and with Congress.

"Our system's full. Our country is full," Mr. Trump said over the weekend.



Mr. Trump has privately fumed for months about the increased flow of undocumented migrants, and congressional opposition to tightening asylum laws or speeding deportation.

Speech writer and immigration hawk Stephen Miller won a crucial internal battle in late March when the president gave him control over immigration policy and Homeland Security personnel.

"One of the great tragedies that is going on in our country today is the loopholes in our immigration laws," Miller said on "Face the Nation" in 2018.

Senior adviser and son-in-law Jared Kushner had been lobbying Mr. Trump to work with Congress in pursuit of new laws. But the president refused and gave new power to Miller, who is looking to revive the family separation policy and close ports of entry.

"At stake is the question of whether or not the United States remains a sovereign country," Miller said.

Miller – and the president – now appear determined to use immigration to motivate the president's base and portray Democrats as soft on security.



"The mass illegal immigration across our border is a direct consequence of Democrat-supported loopholes," Mr. Trump said last month.

In the process, the president is creating massive unrest inside the country's third-largest agency, one with crucial obligations, ranging from domestic terror surveillance and prevention, to cybersecurity, to the Secret Service – even the Coast Guard.

Republicans are fretting about the turmoil and praising the stability Nielsen represented.

"Her grasp of the issues and dedication were major assets for the department," Senate Majority Leader Mitch McConnell said.

"I know Director Cissna," Sen. Chuck Grassley said, adding, "It would be a real mistake if they go that far down into the bureaucracy to fire good people like that."

Adding to the president's border frustrations: a federal judge in California blocked an administration asylum seeker policy that returns migrants back to Mexico after entering the U.S. illegally while their requests are processed. Late Monday night, the president shot back, saying it was "unfair" to the U.S. and "out of control."