Has Washington gone mad? Many Americans - and non-Americans - might have wondered this in recent weeks, amid the drama surrounding the debt ceiling. Never mind the mind-boggling fiscal numbers being tossed around: the real shock for most observers, particularly outside the US, is the degree of polarisation, even extremism, on display.

On one side of the spectrum, Tea Party activists have been brandishing the constitution and declaring “no surrender” on fiscal issues, even at the risk of sparking an American default. On the other side, leftwing parts of the Democratic party have been equally intransigent. Added together, they have produced a toxic gridlock that has not just baffled many non-Americans (say, those Chinese holding US Treasury bonds) but left many Washington observers horrified, too.

While rowdy battles have always been a feature of American politics, what makes the recent spectacle so striking is the sheer sense of poison and lack of common meeting points. Sandra Day O'Connor, the retired Supreme Court justice, for example, recently told a conference in Washington that in times of crisis she would use beer and Mexican food to forge harmony when she was a leader in the Arizona legislature. “I'd get everybody together and cook Mexican food, and we'd sit around outside and eat and drink beer, and make friends with each other.