If the three controversies that beset the Obama administration last week, the most serious accusation came from the story with the least political sizzle. The fallout from the Benghazi terrorist attack derived its potency from the four deaths that resulted. And the ill-advised targeting of conservative groups by the Internal Revenue Service aroused the most visceral response, from the president on down.

But it was the secret probing of journalists’ phone calls that potentially signified the worst abuse of power.

It signals the need for Congress to reconsider and pass a federal shield law that could have safeguarded the identity of the sources used by the reporters in the case. And it underscores the reason why Hawaii needs its soon-to-expire shield law reinstated, to protect whistleblowers from excessive government intrusion.

The more recent case in Washington, D.C., showed a shockingly egregious lack of government restraint. It involved the decision by the U.S. Department of Justice to pursue phone records of Associated Press staffers following a leak of classified information about a failed al-Qaida plot.

The uproar shown at last week’s House Judiciary Committee hearing arose less from a concern for journalists than from the GOP’s hostile relationship with U.S. Attorney General Eric Holder, who said he had recused himself from that probe and answered few questions.

Regardless, the fact remains that the episode is not only the latest example of the Obama administration’s aggressive hunt for whistleblowers in an attempt to plug its leaky ship. It is the most worrisome one, because it shows a White House that recognizes few privacy constraints.

According to the administration, the release of the information could have endangered national security. That may be so, but the AP did agree to delay the story, at the administration’s request, until the administration’s concerns were allayed.

What’s really galling is that Justice rewarded that gesture with a wide-ranging subpoena of phone records, with no oversight from a judge or anyone else.

This is simply intolerable in a government that is supposed to maintain a careful balance of power among its branches. Even in instances when national security concerns might warrant a probe, there must be a third-party review, perhaps by the Foreign Intelligence Surveillance Court.

The Obama administration has tried to stanch the bleeding over this controversy by throwing its support to the Free Flow of Information Act, previously introduced in 2009. It would protect journalists from being forced to testify about confidential sources. The government would have that prerogative only when all other avenues of investigation are exhausted and only if exposure is in the public interest.

In any event, the president should ratchet down its crackdown on whistleblowers. It may have the technical authorization of the law on its side in the exercise of that power, but that fact doesn’t make executive witch hunts a healthy thing in a democracy. The law needs to change.

Hawaii lawmakers, meanwhile, should see the federal case as a Exhibit A in favor of restoring Hawaii’s own shield law. The federal show of arrogance to the AP threatens not only journalists’ practice of their profession, it frightens away those willing to share information. And that compromises the public right to know what its own government is up to.