Jay Carney says it was a simple calculation. He could continue as a reporter and writer for the rest of his working life, or he could try something new and different.

He chose something different. After 20 years as a reporter at Time magazine, Carney accepted an offer to become communications director for Joe Biden, the newly elected vice president, in late 2008. Carney would go on to become President Obama’s press secretary two years later. “I had a great job” at Time, Carney says. “I’d also been doing it for 20 years. Doing something completely new has an appeal.”

As it happens, Carney was an early adopter. He was among the first of what has turned out to be a parade of journalists who’ve turned in their press badges for work in the Obama administration. In a trend that has raised some eyebrows among Obama’s critics, at least 20 reporters and editors from mainstream news organizations have taken high-profile positions in the administration within the past five years.

The latest hire: Richard Stengel, Time magazine’s managing editor (and Carney’s former boss). Obama nominated Stengel last week to be the State Department’s undersecretary for public diplomacy and public affairs, a top communications post. Stengel will succeed Tara Sonenshine, another journalist (ABC News, Newsweek) who became part of the government she once covered.

At State, Stengel can swap newsroom stories with Samantha Power, a former journalist (U.S. News, the Boston Globe, the New Republic) who is now the U.S. ambassador to the United Nations. His staff will include Desson Thomson, a former Washington Post movie critic who became a speechwriter for Hillary Rodham Clinton when she served as secretary of state. Other colleagues will include two recent additions to Secretary of State John F. Kerry’s staff: Glen Johnson, a longtime political reporter and editor at the Boston Globe, and Douglas Frantz, a reporter and editor who has worked for the Los Angeles Times, the New York Times and, most recently, The Post. Frantz was also briefly an investigator for the Senate Foreign Relations Committee, chaired by Kerry, then a senator from Massachusetts.

Every administration draws in a few journalists, typically as speechwriters and press secretaries, a natural given the overlapping skills. A young reporter named Diane Sawyer went to work in Richard Nixon’s press operation in 1970, eventually helping Nixon write his memoirs. Tony Snow, the late columnist and Fox News host, wrote speeches for George H.W. Bush and served as the press secretary for George W. Bush from 2006 to 2007.

Edward R. Murrow, the legendary CBS anchor and perhaps the most famous newsman in America at the time, headed President John F. Kennedy’s U.S. Information Agency, overseeing the U.S. government’s broadcasts around the world.

But Obama may be different in terms of the sheer number of ink-stained wretches and other news-media denizens that he has attracted. Even before he was in office, his campaign had hired former CBS and ABC News correspondent Linda Douglass as a senior strategist. Douglass went on to serve as the communications chief for the White House Office of Health Reform before leaving in 2010.

The pattern of Obama hires has periodically aroused suspicions about the media’s allegedly cozy relationship with the president. Prompted by Stengel’s appointment last week, conservative radio titan Rush Limbaugh commented on his program, “There’s an incestuous relationship that exists between the Washington press corps and any Democrat administration. . . . Journalists are simply leftists disguised as reporters. They’re political activists disguised as reporters. That’s all they are, and this is just the latest example.”

Journalists who’ve become former journalists say it’s a lot more complicated than that.

Jill Zuckman, who was a seasoned political correspondent for the Chicago Tribune, says she joined Team Obama (as head of public affairs at the Transportation Department) in February 2009 primarily because a Republican, Rep. Ray LaHood (Ill.), had been appointed to run it.

“I probably would not have done it without a professional relationship with Ray LaHood,” says Zuckman, who had covered LaHood when he was a congressional staff member in the early 1990s. “He was one of my favorite members of Congress. I thought he was smart, frank and plugged in. I thought I could help him” in his new job.

Zuckman, who left Transportation in 2011 to join a communications firm run by Democrats Anita Dunn and Hillary Rosen, denies any tilt for Obama or Democrats while she was a journalist. “I was a straightforward reporter,” she said. “I had good relationships with Republicans as well as Democrats.”

Carney makes no secret of his loyalties to Obama now but defends his objectivity and professionalism as a journalist when he covered candidate Obama and Washington generally. “I was definitely excited by and privately supported Obama in 2008,” he said. “But I think any reading of my coverage as a reporter would show that I was not an ideologue. [Time columnist] Joe Klein said he thought I was a Republican” when Carney joined Biden’s staff.

What’s more, the news business’s financial troubles have played a significant role in driving journalists onto the job market. The Obama administration came in as the Great Recession worsened what already had been a bad slump for traditional media outlets. Since then, mainstream news organizations have shed thousands of jobs.

“The news business was going south,” says Thomson, who accepted a buyout from The Post in 2008 after 25 years at the paper. “We are at a time when reinvention is the new black. And in 2008, that’s what was in front of me, to reinvent.”

(Thomson and Frantz are among the cadre of former Post journalists who have found second careers in federal Washington. Others include former city editor Bill Miller, now a spokesman for the U.S. attorney in Washington, and former political reporter Shailagh Murray, who replaced Carney as Biden’s communications czar in 2011.)

Peter Gosselin, an economics reporter at the Los Angeles Times, became Treasury Secretary Timothy F. Geithner’s chief speechwriter in 2009, just a few weeks after the Times’s parent, Tribune Co., filed for bankruptcy-court protection. “I couldn’t trust that I’d be able to support two kids through school, and in a few years going to college, on the chance that [newspapers] were not going to collapse,” Gosselin said.

Journalists who became Obama operatives speak highly of the experience. Although they say the office “culture” is wholly different — more collaborative, less geared to a newsroom’s individual star system — the job can be no less rewarding.

“I’m liking it a great deal,” said Thomson. “From the State Department’s point of view, the world is the ultimate canvas and the U.S. role in the world is as big a subject as it gets. . . . You go from outsider to insider, but that doesn’t mean you stop using the skills you applied to journalism.”

Zuckman, who oversaw the Transportation Department’s communications efforts during Toyota’s massive recalls of vehicles to fix a problem with sudden acceleration, said her stint at the agency gave her an appreciation for the hard, fast and complicated work that government employees do. Working for the agency, she said, “turned out to be one of the great experiences of my life.”

But Gosselin advised those who are considering such a switch to think twice.

“What astounded me was what a sleek, well-oiled, 21st-century machine a newsroom looks like compared to the way it works inside government,” he said. “The cultures are really, really different, particularly at high levels,” he added, citing the “messy” government decision-making process in which dozens of people get a say.

After working for Geithner and as a special adviser for health reform at the Department of Health and Human Services, Gosselin is now a senior health-care policy analyst for Bloomberg Government, a news and information source. Which makes him part of an even smaller fraternity: those who’ve made a full revolution through the revolving door between reporting and government.