Later this month six Americans will be honoured with a Ridenhour prize which celebrates truth-telling in the public interest.

They are a varied bunch. Eileen Foster helped expose systemic fraud at America's largest mortgage provider Countywide Financial. Lt Col Daniel Davis spoke out against the top brass's portrayal of US military actions in Afghanistan while he was still a serving soldier. Author Ali Soufan wrote The Black Banners, a history of Al-Qaida. The two makers of Semper Fi – a documentary about a Marine's investigation into the death of his daughter – gets a Ridenhour for film and Congressman John Lewis – a hero of the Civil Rights struggle – gets a courage award.

All spoke out even when the forces arrayed against them were large, powerful, or questioned their motives and patriotism. That should be something that the Barack Obama administration would celebrate. After all, this is a White House that once vowed to protect whistleblowers when it drew up its transition agenda. "Such acts of courage and patriotism, which can sometimes save lives and often save taxpayer dollars, should be encouraged rather than stifled," the document said as Obama prepared to take power.

But that was then. This is now.

Over the past three and a half years the Obama White House has instead shown a ferocious hostility to many whistleblowers and earned itself the ire of progressive columnists like Salon's Glenn Greenwald and whistleblower defence groups like the Project on Government Oversight and the Government Accountability Project.

Danielle Brian, of the PGO, has said the US department of justice in the Obama administration "sent a clear of message of fear and intimidation" to whistleblowers in the national security field. This is how the GAP's Jesselyn Raddack – herself a former whistleblower at the DoJ – put it: "While the Bush administration treated whistleblowers unmercifully, the Obama administration has been far worse. It is actually prosecuting them," she wrote recently.

To do that it is using the bluntest of tools: the Espionage Act, a first world war-era law intended to combat the threat from spies, not internal dissenters. So far six whistleblowers have been charged under the draconian law with the last one – CIA veteran John Kiriakou – being indicted on 3 April.

Kiriakou, who was a counter-terrorism expert in Pakistan and helped capture senior Al-Qaida operative Abu Zubaydah, has been a vocal critic of waterboarding. He spoke to journalists and wrote a book about it, calling it torture and exposing it as a deliberate policy, rather than the actions of a few rogues. Now a hefty jail term could be his reward.

Others, from across a spectrum of government departments, include people who have exposed wrongdoing at the National Security Agency or fears at the FBI that Israel might attack Iran. Another at the state department spoke out about North Korean nukes and, of course, there is the suspected WikiLeaks source, army private Bradley Manning.

Defenders of Obama's record on these whistleblowers point to a national security defence and say they actively encourage people to speak out about wrongdoing elsewhere. Whistleblowing may be one thing, they say, but intelligence leaking is another. Every government has a right to protect its secrets. But one can also point to other areas where the Obama administration has shown a love of secrecy that should shame the Democrats who slammed President George Bush for a similar attitude.

For example, the Food and Drug Administration is being sued by current and former employees who say it started monitoring their private emails after they complained that approved medical devices might be risky. Or consider Obama's signing of a new defence law – called the NDAA – which critics have said defines illegal support of terrorists so broadly that journalists could be swept up in it by interviewing sources at radical groups. A group of writers and activists, including a Pulitzer prize-winning former New York Times reporter, have already gone to court in New York arguing the NDAA is chilling free speech around the globe.

Perhaps the Obama administration should perhaps remember who the Ridenhour prizes are named after. That is Ron Ridenhour, a Vietnam veteran who, while on active duty, investigated disturbing rumours of a terrible war crime by US soldiers. He then wrote to Congress to reveal an event that caused headlines around the world: the massacre at My Lai. Many in the Obama White House would agree that Ridenhour was a real American hero. But if he did what he did today, in Iraq or Afghanistan, just as Kiriakou has done, maybe they would prosecute him.