Whatever your opinion of Prime Minister's Questions, it at least provides an opportunity for the opposition parties to put the government on the spot and require its leader to defend his or her policies. Conversely, it allows the Prime Minister to respond to these criticisms, so that if they are themselves dishonest in some way they will be less effective than if they had simply been distributed through an uncritical media.

America, with its President separate from the legislature and often removed from the legislative process, has no such institution. John McCain promised to introduce one during the last presidential campaign. But for a taste of what it might look like, and how healthy it could be, I recommend that you watch this riveting and almost unprecedented exchange between President Obama and the congressional Republicans at the GOP Retreat in Baltimore on Friday:

(Points for discussion: is it simply my support for him that makes me think he came out better here? Is his concern about the effects gridlock and polarisation could have on America warranted? If this event became a regular institution, how would it change the character of American politics and of those who ran for President? How would Sarah Palin perform in such a setting?)