After the Cold War ended, and again after the Sept. 11 attacks, a string of C.I.A. directors and congressional overseers pushed the agency to diversify its ranks.

The drive had little to do with any sense of racial justice, civil rights or equity. It was, rather, a hard-nosed national security decision.

The agency’s leaders had come to believe that having analysts from an array of backgrounds would lead to better conclusions. Officers with cultural knowledge would see things others might miss. Case officers who reflected America’s diversity would move about foreign cities more easily without being detected.

“If there is one place that there is a clear business case for diversity it is at the C.I.A. and intelligence agencies,” said Senator Mark Warner, a Virginia Democrat who is a longtime senior member of the Senate Intelligence Committee. “You have to have spies around the world in all countries. They can’t all be white men, or our intelligence collection will suffer.”

But what was once a bipartisan emphasis on the importance of diversity at the agency is facing new pressure. Under the Trump administration, the C.I.A. has moved to dismantle its recruitment programs, especially those that have sought to bring racial and ethnic minorities into the organization, which is mostly white.

John Ratcliffe, the C.I.A. director, says those steps are about making a colorblind organization solely focused on hiring and promoting people based on merit.