As the opening summer act of the campaign draws to close, attention is turning in Phase 2 to the serious matter of the economy. It’s no longer about Mike Duffy. The most important thing each leader will have to face now is the issue of economic credibility. For Liberal Leader Justin Trudeau, it’s a huge deficit gamble. For Prime Minister Stephen Harper, it’s the eroding effect of a bad economy. And for NDP Leader Thomas Mulcair, it’s a surprising tack to the right.