“Whatever it takes.” Mario Draghi’s declaration that he would save the euro could well go down as the most effective three-word statement by a Roman since Julius Caesar’s veni, vidi, vici.

The president of the European Central Bank’s statement, followed up with a portentous and vaguely threatening – “and believe me it will be enough” – was made in July 2012. Almost two years later, Mr Draghi’s intervention is widely regarded as the turning point in the euro crisis. Investors who were running screaming from the eurozone in the summer of 2012 are now rushing back in.

But whatever the thundering herd of investors may think, it is too soon to declare that Mr Draghi has won the war for the euro. The eurozone still faces deep underlying economic and political problems that are beyond the control of the president of the ECB and his colleagues.