The European Union's 19th crisis summit was winding down when European Central Bank President Mario Draghi made an unusual request. He wanted some alone time with EU President Herman Van Rompuy to thank him for charting the path toward a shock-proof euro zone.

Only later did the significance of the blueprint sketched out at the June summit in Brussels emerge. The commitment to tighter bank supervision, budget coordination and a nebulous "political union" was instrumental in persuading Draghi that governments are putting the currency on a sounder footing, leading to yesterday's ECB decision to buy bonds to help them get there.

"We need two legs," Draghi said in presenting the new tactics. "Governments have to undertake the policy reforms. There is no intervention by the central bank, by any central bank, that is actually effective without concurrent policy action by the governments."