If leadership is measured by seizing big opportunities that others do not see, then Barack Obama is already proving himself a leader. His 2007 decision to run for president was audacious but shrewd. He saw the opening. Now, he has judged that the severe economic crisis, his own soaring popularity and Republican disarray provide a rare chance to revolutionise US domestic policy. And he is going for it right now.

His new budget calls for breathtaking change in one big step. In the modern era, only Lyndon Johnson in 1965 and Ronald Reagan in 1981 have sought and achieved comparable change. Johnson’s Great Society sharply expanded the government’s role. Reagan rolled that back. Now, Mr Obama is proposing a new era of progressive government, centred on expanded federal roles in energy, health and education.