Shortly after she became Prime Minister in 1979, Margaret Thatcher was showing a guest around 10 Downing Street. On the way up the main staircase, she pointed out the portraits along the wall of England's Prime Ministers, from William Pitt (1783-1801) to her predecessor, James Callaghan. The visitor remarked that there was no room left for Thatcher's picture. "Don't worry," she said with the trace of a smile, "I'll push all the others down."
She did something even better last week. In the most impressive electoral sweep by any British party since 1945, Thatcher's Conservatives won 397 seats in the...