The failure of the “Super Committee” last year to reach a budget deal underscored the underlying wedge in US politics. For most of the post-1945 years the electorate has been slightly to the left or right of centre, spread around a dominant middle ground. This enabled compromises in legislation to be reached with relative ease.

But a political tsunami has emerged out of our past in the form of the Tea Party, with its ethos reminiscent of rugged individualism and self-reliance. That was a dominant force for more than a century but has faded since the New Deal. The Tea Party has yet to obtain sufficient traction to forge majorities for new legislation. But its influence beyond its numerical strength has created an effective veto of new legislation before the current heavily Republican House of Representatives. It has so altered the distribution of votes within Republican Party’s House caucus that the party’s centre has moved closer to the Tea Party. Moreover, the heavy House Democratic losses of moderates in 2010 shifted the centre of gravity of their caucus to the left. This has created something of a bimodal distribution leaving a much diminished centre. The Senate, although less affected by the 2010 election has not been immune from this shift. The days of Senators Pat Moynihan, Howard Baker and Lloyd Bentsen seem a long time ago.

The emerging fight over the future of the welfare state, a paradigm without serious political challenge in eight decades, is accentuating the centre’s decline. The welfare state has run up against a brick wall of economic reality and fiscal book-keeping. Congress, having enacted increases in entitlements without visible means of funding them, is on the brink of stalemate. As studies by the International Monetary Fund have demonstrated, trying to solve significant budget deficits mainly by raising taxes has tended to foster decline. Contractions have also occurred where spending was cut as well, but to a far smaller extent.