PARIS – Financial markets have rallied since July on the hope that the 
global economic and geopolitical outlook will not worsen, or, if it 
does, that central banks stand ready to backstop economies and markets 
with additional rounds of liquidity provision and quantitative easing. 
So, not only has good – or better-than-expected – economic news boosted 
the markets, but even bad news has been good news, because it increases 
the probability that central-banking firefighters like US Federal 
Reserve Chairman Ben Bernanke and European Central Bank President Mario 
Draghi will douse the markets with buckets of cash.But markets that rise on both good and bad news are not stable markets. “Risk-off” episodes, in which investor sentiment sours, are likely to return if economic news worsens and confidence in policymakers’ effectiveness drops.
In
 the eurozone, euphoria followed the ECB’s decision to provide support 
with potentially unlimited purchases of distressed countries’ bonds. But
 the move is not a game changer; it only buys time for policymakers to 
implement the tough measures needed to resolve the crisis. And the 
policy challenges are daunting: the eurozone’s recession is deepening as
 front-loaded fiscal consolidation and severe credit rationing 
continues. And, as eurozone banks and public-debt markets become 
increasingly balkanized, establishing a banking union, a fiscal union, 
and an economic union while pursuing macroeconomic policies that restore
 growth, external balance, and competitiveness will be extremely 
difficult.