Under both sides of politics, ministerial responsibility has steadily diminished in recent decades. The idea that the buck stops with ministers has now become a historical relic. After Bob Collins rode out the pay-TV debacle under Labor in 1994, the only basis for ministerial resignation became personal wrongdoing or mistakes by ministers themselves. Mistakes or wrongdoing by their bureaucrats or ministerial staffers were no longer the basis for resignation.

The caveat to that, notionally, remained misleading Parliament, long considered to be the political equivalent of a capital offence. A minister found to have misled Parliament was expected to resign. But that, too, began to slip: John Howard plainly misled Parliament about meeting Manildra’s Dick Honan in 2002 but refused to resign and insisted, contrary to Hansard, that he hadn’t misled anyone.

The circumstances around Julie Bishop misleading Parliament on the letter from Man Haron Monis to George Brandis are more serious than whether John Howard was lobbied by a business mate. The handling of the letter, and the convenient failure of the Attorney-General’s Department to provide it to the government’s inquiry into the Sydney siege, represent a significant error on a major national security issue. Bishop misled the House in claiming it had been referred to that inquiry, and senior officials within Prime Minister and Cabinet, Attorney-General’s and the Prime Minister’s own office failed to take any action to correct the record upon learning of the House being misled until several days later — and even discussed ways to talk around the fact that the House had been misled. This is plainly the stuff of cover-ups.

Bishop has been placed in this position due to the incompetence of AGD; she represents Brandis in the House of Represenatatives and must rely on AGD advice. Even under a strict interpretation of ministerial responsibility, there’s no clear case for her resignation. But the bureaucrats and staffers in the PMO, PM&C and AGD who allowed Parliament to remain misled have no excuse. They should resign or be sacked.

Misleading Parliament on an important national security matter must, surely, still mean something.