It was a peculiar group that slipped, quietly, into a restaurant called Upstairs on the Square, near Harvard University, for lunch last Tuesday. Over hamburgers and crab cakes, Pat McFadden, Tony Blair's political secretary, chatted amiably with Robin Cook, one of the Prime Minister's harshest critics. The Liberal Democrat Charles Kennedy, Sir Menzies Campbell and Lord Razzall exchanged pleasantries with Matthew Doyle, Labour's chief press officer. Had they known about the event, Labour backbenchers might have suspected a secret attempt to renew the Lib-Lab pact. In fact, the eclectic collection of politicians, brought together in Boston by a Liberal-leaning lobbyist,...