US - US President are used to deference and barking orders - not wiping egg from their faces.
So it was unpalatable for Mr Barack Obama to go on television on Monday and admit glaring failures in the rollout of the health-care law that bears his name.
Website snafus that have slowed sign-ups for Obamacare in the three weeks since its launch are embarrassing on multiple fronts for the White House and represent a ballooning political challenge.
The idea that government can work is also at the centre of Mr Obama's political creed - and is a driving motivator of his ideological clash with Republicans. So any evidence to the contrary is inconvenient, to say the least.
But the faulty debut of the Healthcare.gov website is spurring questions over Mr Obama's competence in implementing a law he wagered his presidency to pass three years ago, but which has yet to deliver a political payoff.
The embarrassment is even more acute as Mr Obama built his career on exploiting the power of the Internet to build a political movement.
The Obamacare storm was building for days, but was obscured by the furore over a just-avoided debt default, and a government shutdown.
The White House, however, sensed that the row was about to break through and, over the weekend, made it clear that Mr Obama would address the website glitches head on.
But his appearance in the White House Rose Garden was less a mea culpa than a sales job.
"The product is good," Mr Obama insisted, apparently worried that bad reviews of the website would sour Americans even further on Obamacare.
The botched rollout, which he described as being plagued by "kinks", offered an opening to Republicans stung by coming off second best in the shutdown drama.
"Every day that there are problems with the Obamacare website is going to be a day where the Republicans say this is Obamacare writ large," said Dr Dante Scala, a political-science professor at the University of New Hampshire.