For Weidmann, putting Europe's monetary union on a sound footing involves governments either giving up some sovereignty over national budgets or setting stricter fiscal rules and ensuring they're enforced. Neither has happened yet, he said during a March 28 speech at Chatham House in London. While charming his audience with humor and a down-to-earth style, Weidmann offered a sobering assessment.

"The time has come to move from containing the crisis to resolving it," he said. "If we have the will to make the right choices, we will be able to rebalance Europe and lay the foundation for a stronger, more stable monetary union."

And:

Yet his habit of serving unpalatable truths to former political masters and fellow monetary policy makers isn't winning him friends, said Nick Kounis, head of macroeconomic research at ABN Amro in Amsterdam.

"I don't really think that fellow policy makers are happy that he's coming up with this," said Kounis. "Disagreements on the Governing Council, especially between the Bundesbank and the president, can create a lot of uncertainty about the future course of policy. It can also lead to credibility issues for the central bank."

Critics of Weidmann's approach include billionaire investor George Soros, who said rising tensions in financial markets reflect concern that the Bundesbank is preparing for the end of the euro.

The German central bank is campaigning against "indefinite expansion" of the money supply and seeking to limit losses it would face if the euro splintered, Soros said in a speech in Berlin on April 12. "This is creating a self-fulfilling prophecy."

Things have not gone Weidmann's way as the debt crisis presented the ECB with challenges few foresaw. He was outvoted on Aug. 4 when soaring yields in Italy and Spain prompted the ECB to resume and expand its bond-purchase program, a decision that prompted chief economist Juergen Stark, a former Bundesbank vice president, to quit. Weidmann later insisted the ECB should reduce its exposure to risky assets, which it was accumulating after allowing banks to use lower-quality collateral for central bank loans.

"The balance sheet of the Eurosystem is burdened with considerable risks," he said on Sept. 13. "I am of the conviction that these should now be reduced and under no circumstances expanded."

Six months later, the ECB's balance sheet had swollen by almost 40 percent to 3 trillion euros ($3.9 trillion) after policy makers flooded the banking system with more than 1 trillion euros of three-year loans to help avert a credit crunch.

David Fuller's view Following Juergen Stark's resignation Jens Weidmann now carries the banner for the Bundesbank's soul in what is clearly a losing clause. It is no secret that the Bundesbank never wanted the euro, knowing that it could only significantly diminish its influence over fiscal discipline. And so it has proved and that is the price Germany has to pay for the political construct known as the euro, at least under its current membership of countries.