Can Opec get its mojo back in St Petersburg?

Ecuador is doing what other members wish to—ditching a supply deal that has become more painful than gainful. Saudi Arabia needs to revive momentum

Ecuador is too small to be a deal-breaker for Opec. But when its oil minister Carlos Perez announced on 18 July that, needing cash, his country would sling its production quota and start lifting output again, it summed up Opec's problem. When prices rise to compensate for output cuts, great. But Brent, at around $49 a barrel on 19 July, is 9% beneath its level when Opec extended its deal at the end of May. If you think prices aren't going to move much higher soon, then it's rational to pump more while you can. Other members itch to do the same. Iran and Iraq both strain at the leash. They and Angola both upped their output marginally in June. Saudi production also rose, though remains in lin