As Europe stumbles into 2015, dogged by weak growth and the prospect of deflation, Draghi is on the verge of launching mass purchases of government bonds with new money - also known as quantitative easing (QE) - in the hopes of jolting Europe's economy into life.
But this time, it is unclear whether he can count on the same clear support from Berlin.
Without it, the effectiveness of any QE program could be undermined. More fundamentally, a rift between Germany and the ECB would herald a dangerous new phase for Europe in which the bloc's two most important shapers of policy are at odds.
In a rare four-page interview with German daily Handelsblatt on Friday, Draghi appeared to go out of his way to reach out and avert such a clash, saying the risk of the ECB failing to preserve price stability had risen and it may need to act to meet its mandate.
"Germany's position on the QE program is arguably the single most important issue for the ECB right now," said Marcel Fratzscher, head of the DIW economic institute in Berlin and a former official at the ECB. "Support from both Merkel and (Finance Minister Wolfgang) Schaeuble will be absolutely vital."
What has changed since 2012?
For one thing, fears of a euro breakup have subsided. That has made it easier for German officials to push back against policies they disagree with.
Read MoreEuro area: Wars, Greece and "whatever it takes" QEs
The worry in Berlin is QE will reduce pressure on struggling southern euro countries to reform. Some think pumping new money into the system would sow the seeds of a future crisis.
"If the ECB isn't careful about how it does QE the reaction in Germany will be fierce," said a senior German official who requested anonymity due to sensitivities over ECB independence.
"If QE does happen, as it certainly looks like it will, it should happen in a way that doesn't see it undermined by German politicians. Draghi needs to know what the red lines are."
Complicating the debate is the rise of the Alternative for Germany (AfD), a eurosceptic party that didn't exist back in 2012.
After sweeping into three regional parliaments in eastern Germany last year, the AfD will try to win its first seats in a western assembly when Hamburg votes in mid-February.
A QE program, which the markets expect to be unveiled as soon as the ECB's next policy meeting on Jan. 22, could play into the AfD's hands.
Uncertainty surrounding a Jan. 25 election in Greece, which could vault the left-wing Syriza party into power, has muddied the waters further by raising the risk of a sovereign default and severe losses for the ECB on any Greek bonds it holds.
Should the ECB unveil a QE program that includes Greece before the political outcome in Athens is clear, it would be impossible for the German government to remain silent, several officials said.