FILE - In this Saturday June 7, 2014 file photo, former Virginia Attorney General Ken Cuccinelli addresses the Virginia GOP Convention in Roanoke, Va. President Donald Trump’s anointment of Cuccinelli as acting head of a major federal immigration agency has prompted muttering from Republican senators whose job descriptions include confirming top administration aides. But it’s not gone beyond muttering. Their reluctance to confront Trump comes as veterans of the confirmation process and analysts say he’s placed acting officials in key posts in significantly higher numbers than his recent predecessors. (AP Photo/Steve Helber, File)

WASHINGTON (AP) — President Donald Trump’s latest anointment of an acting head of a major federal agency has prompted muttering, but no more than that, from Republican senators whose job description includes confirming top administration aides.

Their reluctance to confront Trump comes as veterans of the confirmation process and analysts say he’s placed acting officials in key posts in significantly higher numbers than his recent predecessors. The practice lets him quickly, if temporarily, install allies in important positions while circumventing the Senate confirmation process, which can be risky with Republicans running the chamber by a slim 53-47 margin.

The latest example is Ken Cuccinelli, who last week was named acting director of U.S. Citizenship and Immigration Services. He is an outspoken supporter of hard-line immigration policies and his appointment was opposed by some key Senate Republicans.

Definitive listings of acting officials in Trump’s and other administrations are hard to come by because no agency keeps overall records. Yet Christina Kinane, an incoming political science professor at Yale, compiled data in her doctoral dissertation, “Control Without Confirmation: The Politics of Vacancies in Presidential Appointments.”

Kinane found that from 1977 through mid-April of this year — the administrations of President Jimmy Carter through the first half of Trump’s — 266 individuals held Cabinet posts. Seventy-nine of them held their jobs on an acting basis, or 3 in 10.

Under Trump, 22 of the 42 people in top Cabinet jobs have been acting, or just over half.

And though Trump’s presidency has spanned only about 1 in 20 of the years covered, his administration accounts for more than 1 in 4 of the acting officials tallied. Kinane’s figures include holdovers from previous administrations, some of whom serve for just days.

“This is not a new thing,” Kinane said of presidents’ use of acting officials. “It is, however, a considerably higher number” under Trump, she said.

While Republicans widely blame Democratic opposition to Trump’s nominees for his use of acting officials to fill some posts — a characterization Democrats reject — many also say his reliance on that alternative is costly.

“It has the potential to spill over into other nominations that the president’s prioritized,” Sen. Marco Rubio, R-Fla., said of Cuccinelli’s appointment. Sen. Susan Collins, R-Maine, said acting officials have “tenuous footing” for overseeing their agencies.