The ECB's balance sheet, if needed

A central bank can undertake two principal actions: actively stimulate the economy and passively promote lending (see Hetzel, 2012, especially chapters 14 and 16 for the theory and application to the Great Recession in the United States). Active monetary stimulus of the economy is normally achieved by reducing its policy interest rate. The market's expectation of how long the policy rate will remain low determines the extent of the decline in long-term interest rates and the consequent increase in investment. When the policy rate falls to zero, the central bank can buy financial assets to directly lower the long-term interest rate, an action often described as "quantitative easing."

In contrast to active monetary stimulus, the central bank can passively provide funds to banks in the hope they will lend more to release credit constraints on economic growth. However, there is no guarantee that the banks will use their easier access to funds for new lending.  

By these conventional categories, the ECB provided no active stimulus. Policy interest rate reductions always lagged behind the fall in activity; indeed, interest rates were raised in 2008 and, more disastrously, in 2011 (Hetzel, 2014). And, the ECB has been virtually absent in the purchase of assets to directly influence long-term rates.  

The ECB did provide banks with additional "liquidity." But, in doing so, it acted in a manner highly unusual for central banks. For an extended period, the ECB's so-called liquidity operations have, in effect, propped up insolvent banks and have thus been a giant exercise in forbearance.

Consider the evidence.