One was that we should cut Greece off from central bank financing, which would have implied the full collapse of the Greek economy and the likely exit of Greece from the euro area. The other view was that we should provide unlimited, unconditional liquidity to the Greek government and the Greek economy no matter what.
The former option would have meant the ECB triggering events of momentous political importance with potential implications for its mandate – the type of decision, moreover, that falls within the jurisdiction of elected authorities. The latter option, however, would have meant potentially engaging in monetary financing or funding banks without adequate collateral, thereby violating the Treaty.