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, while Sen. Lisa Murkowski, R-Alaska, said she wants confirmed department chiefs because she "wants to know who's on point" for the administration on issues.
Yet no Republicans said they had challenged Trump's use of acting officials. Many of them complained openly when President Barack Obama named special White House advisers informally called czars. And a year after President Bill Clinton named civil rights lawyer Bill Lann Lee acting attorney general for civil rights in 1997, Congress passed a law limiting the time acting officials can serve, generally to no more than 210 days.
"I don't know who spends their day worrying" that their acquiescence was fraying the Senate's constitutional power to advise and consent on nominees, said Sen. John Cornyn, R-Texas.
Democrats and experts disagree on the importance of the Senate's role.
"They're almost like they're willing to act as staff members (of the White House) rather than independent senators," said Sen. Patrick Leahy, D-Vt., a senator since 1975.
"They're not standing up for their own institution," said Kathryn Dunn Tenpas, a nonresident scholar at the Brookings Institution who has studied White House staffing.
Cuccinelli, a former attorney general of Virginia, has taken hard-line positions on immigration, such as opposing citizenship for American-born children of parents living in the U.S. illegally. He once led a conservative group that considered Senate Majority Leader Mitch McConnell, R-Ky., too moderate, and many Republicans doubt Cuccinelli could win confirmation.
"That's probably the only way they could get him in there," the No. 2 Senate GOP leader, John Thune of South Dakota, said of Trump's naming Cuccinelli acting director.
Also in an acting position are two Cabinet secretaries, Kevin McAleenan of the Homeland Security Department and Patrick Shanahan at the Defense Department. Others in the acting roles are Director Russell Vought of the Office of Management and Budget, U.N. Ambassador Jonathan Cohen and White House chief of staff Mick Mulvaney. All but Mulvaney would need Senate approval to become permanent, and Trump has sent the Senate a nominee for just one of those jobs: Kelly Craft to be the ambassador to the U.N.
A White House spokesman did not provide a list of acting officials or comment on why Trump was relying on them, despite requests over several days. Trump has said he likes naming acting officials, telling reporters in January, "It gives me more flexibility."
But one explanation is that under Trump, the process of filling jobs has been slow and riddled with missteps.
Trump has withdrawn 63 nominees so far, doubling the 31 Obama retracted at this point in his first term, according to the nonpartisan Partnership for Public Service, which studies ways to improve government effectiveness. He's also decided against nominating some candidates after realizing the GOP-led Senate would reject them, including two would-be picks for the Federal Reserve: businessman Herman Cain and conservative commentator Stephen Moore.
In addition, Trump's 568 nominations during his first year in office were more than 100 fewer than Obama submitted during that period, partnership figures show.
Max Stier, the group's president and CEO, said Trump's use of acting officials is partly because his campaign's preparations for its transition into power were "the worst of any recent president." But he said a desire to avoid difficult or rejected Senate confirmations "does appear to be one element, and the most obvious example of that is Ken Cuccinelli."