[j2labs]

This is an easy one to understand.

Krugman was a proponent of mass inflation, aka. helicopters of money, as a solution to the credit crisis. Bitcoin makes it basically impossible to manipulate the money supply the way the Fed has done to navigate the 2008 crisis.

Krugman sees Bitcoin as a threat to the central banks ability to stabilize the economy.

[seiji]

Also see: the euro crisis.

It isn't a "threat" so much as just foolish.