“If you look at the platforms, the economic platforms of the current Republican candidates for president, they don’t simply defy logic and any known economic theories, they are fantasy,” Obama said.

In a time of extreme policy confusion, 3% GDP growth is one of the only firm targets we have to hang onto. The problem is that in interview after interview, Donald Trump and his surrogates have demonstrated that they have no idea how to get there.

Remember when Donald Trump lambasted his predecessor Barack Obama (and often) about how weak the economic recovery was during the Obama presidency? It was the weakest growth post-recession ever, Trump reminded us. And he was right about that. If the World Bank's latest forecast -- released this week -- is right about global GDP growth, Trump will wish he had Obama's numbers.