Trump Loyalists Across Homeland Security Could Vex Biden’s Immigration Policies

Those agents may have gotten a lift in the waning days of Mr. Trump’s administration, when Trump loyalists tried to codify the influence of those unions. The day before Mr. Biden’s inauguration, union leaders signed a labor agreement with Kenneth T. Cuccinelli II, an immigration hard-liner and the acting deputy secretary of the Department of Homeland Security, that requires ICE’s political leadership to consult with the union on policy decisions.

If the agreement stands, it could undercut Mr. Biden’s directives to the enforcement agency, including guidance that took effect on Monday requiring ICE officers to focus arrests on violent offenders.

“They are not going to be able to get people to change their deeply held convictions,” Stephen Miller, the architect of Mr. Trump’s immigration policies, said of many career officials at the Homeland Security Department. “They are going to make painfully clear to the politicals what the consequences are going to be if their advice is not followed.”

The emergence of an emboldened resistance inside the Biden administration is not limited to the homeland security agencies. Pockets of government employees loyal to Mr. Trump and his agenda remain ensconced in other parts of the bureaucracy.

Andrew Veprek, an ally of Mr. Miller’s and once the deputy assistant secretary of state for refugees and migration, has been succeeded by a veteran of President Barack Obama’s administration. But Mr. Veprek, a career Foreign Service officer, has returned to the State Department.

Michael Ellis, a Trump loyalist, was named as the top lawyer for the National Security Agency in the days before Mr. Biden took office. He has been put on administrative leave while his appointment is investigated, but he remains an employee of the agency. And at the Justice Department, there are still career lawyers who defended many of Mr. Trump’s policies, including the separation of families at the border.

Mr. Biden also faces the politically fraught choice of whether to remove two inspectors general appointed by Mr. Trump: Eric Soskin, the inspector general of the Transportation Department and Brian D. Miller, a former Trump White House lawyer tapped last year to investigate abuses in pandemic spending.