For cases ranging from adultery to illegal gambling, US generals are facing tough punishment for personal misconduct in an online era that has placed the top brass under unprecedented scrutiny.

Misbehavior could be quietly hushed up in the past without disrupting careers. But generals are now disciplined in the public spotlight, military officers and analysts said Friday.

"The bar has gotten higher," said one senior officer, who spoke on condition of anonymity. "And the margin for error has gotten smaller. They are under the microscope."

Last week, the number-two ranking officer overseeing the country's nuclear forces, Vice Admiral Tim Giardina, was fired over allegations he used counterfeit chips at a casino in Iowa.

Two days later, Major General Michael Carey, who was in charge of hundreds of land-based nuclear missiles as head of the 20th Air Force, was removed from his post due to "a loss of confidence and trust."

Carey is under investigation for personal "misbehavior," which officials said allegedly involved alcohol.

Last year, the four-star officer running Africa Command, General Kip Ward, was reprimanded after a probe found he misused funds for lavish travel. Ward was stripped of a star and retired at a lower rank.

In January, US Army Brigadier General Jeffrey Sinclair will face a court martial over alleged forcible sodomy and other charges, in a case rife with sordid allegations.

The military's most prominent general, David Petraeus, was never disciplined while in uniform but was forced to retire last year as head of the CIA after admitting to an affair with his biographer.

The legal rules that apply to generals have not changed but recent high-profile cases have shined a brighter light on the enforcement of those standards, said David Barno, a retired army general.

"What in the past might have been handled by quiet retirement today inevitably goes right to newspaper headlines. And it's not a bad thing," Barno told AFP.

"It's definitely a more transparent world than I think maybe 10, 15, 20 years ago, where these things probably occurred but were handled more quietly out of the public view."

Dismayed over the scandals, the military's top officer, General Martin Dempsey, is overseeing a sweeping review of training and education for generals that aims to place a greater emphasis on ethics and personal character.

Dempsey has said the military needs leaders with both competence and character, and that a decade of war and big budgets had made for "some bad habits."

"I think on a larger scale, we are seeing a tightening of standards in the military coming out of the two wars we've been in," said Barno, now a fellow at the Center for a New American Security.

When generals are exposed for blunders or worse, there is a degree of "voyeuristic interest by people in the military," said Eugene Fiddell, who teaches military justice at Yale Law School.

"It's what I call khaki shadenfreude."

A frequent theme running through the cases is that senior officers, having worked their way up a rigorous system, seem to lose their bearings when they make it to the top.

"It has long fascinated me that people who reach a certain pay grade may conclude that they are bullet proof," he said.

"And it's always a surprise when you see this."

Although held to account for personal misconduct, generals and admirals are rarely if ever fired over their professional performance.

But last month, the Marine Corps sacked two generals for failing to prevent a disastrous attack on a major NATO base in southern Afghanistan -- a decision that sent shockwaves through the military.

It was the first time since Vietnam that generals had been relieved of command over their battlefield performance.

"For some years now there has been a trend toward reduced tolerance for personal misbehavior in senior officers, but this hasn't generally extended to accountability for their professional military performance," said Stephen Biddle, professor of political science at George Washington University.

"Perhaps the Marine Corps action signals a new trend on this score. After 12 years of warfare this would seem overdue," he said.

But other analysts said the military holds top officers accountable at every step of their career, declining to promote them if they fail to make the grade.

"It is true that most of these cases involve personal conduct rather than professional malpractice, but what the critics forget is that the military's 'up or out' promotion system involves regularly holding people accountable, just in the form of not getting promoted," said Peter Feaver, a professor at Duke University.