For most Democrats the 2008 election is about putting the Bush years behind them. But for Hillary Clinton and Barack Obama, who are battling it out for the Democratic nomination, the real argument is about the 1990s.

Barack Obama, whose message of "change" implicitly signals moving beyond the Clintons, usually cites the 1990s to remind people about the politics of "polarisation". In contrast, for Mrs Clinton, whom polls say is marginally trailing her rival in Iowa, the 1990s were all about good government.