Italy's successful bond auction today is a positive harbinger for 2012 -- with a caveat. The government sold 9 billion euros ($11.6 billion) of six-month debt at an average interest rate of 3.25 percent. That yield is exactly half the 6.5 percent rate Italy paid to sell bonds of similar maturity a month ago. At the same time, Italy auctioned two-year notes at a 4.85 percent interest rate, down from 7.8 percent in November.  This could mean Italy will have an easier time in 2012, when it must sell almost 450 billion euros in government paper to finance its debts.

It would be comforting to believe that the bond market is rewarding the Italian government with sharply lower interest rates now that Prime Minister Mario Monti has pushed through an austerity package to cut spending and raise taxes by 30 billion euros.

But the lower yields are probably more the result of last week's back-door move by the European Central Bank to offer 489 billion euros in three-year loans to European banks, which are using at least some of those funds to buy their governments' debt.

The ECB is charging banks less than 1 percent on its loans, and the six-month Italian paper pays 3.25 percent, for a nice 2.25 percent spread. That locked-in spread rises as banks buy longer-term debt. Those returns can then be used to bolster European banks' capital.

It all seems so sensible: The highly indebted sovereigns can now sell their debt at more reasonable rates to their own banks, which can borrow at very low interest from the ECB for a guaranteed return. And the ECB, true to its principles, can claim not to be buying sovereign debt.

The downside? The ECB will have to keep this back-door operation going for years -- until Greece, Ireland, Italy, Portugal and Spain can stabilize their debts and start growing again. To do that, they will have to stay on the austerity path and reform their taxation systems, pension programs and labor markets -- no small tasks.

A bigger test of the ECB's strategic lending to European banks comes tomorrow, when Italy is due to sell as much as 8.5 billion euros of longer-maturity debt.

(Paula Dwyer is a member of the Bloomberg View editorial board.)