Berlin: Germany's defence minister quit on Tuesday amid persistent allegations that he plagiarized parts of his doctoral thesis, depriving Chancellor Angela Merkel's conservative bloc of a man long rated as the country's most popular politician.

Karl-Theodor zu Guttenberg, 39, said he had decided to go 'not just because of my faulty doctoral work' but because the persistent focus on it threatened to overshadow duties such as overseeing a major overhaul of the German military and troops' deployment in Afghanistan.

"It is the most painful step of my life," Guttenberg told reporters in a hastily convened appearance at his ministry. "Because my office, the Bundeswehr, academia and the parties that support me faced potential damage, I am drawing the consequences that I have and would have demanded of others."

Bayreuth University revoked Guttenberg's academic title last week, saying the minister had 'seriously violated' its standards by failing to credit sufficiently some of his sources.

Guttenberg has been the rising star of Germany's center-right over the past two years. He built a reputation as a plain-speaking man of action in a brief stint as economy minister and then, after Germany's 2009 election, as defense minister.

In that job, he pushed through a plan to end conscription — part of an effort to slim down the German military and make it better adapted to an era in which it faces growing demands to deploy overseas. But Guttenberg's crisis management after the plagiarism allegations emerged two weeks ago, and then kept on coming, was less than impressive.

He initially issued a statement describing them as 'absurd', then said he would stop using his title as a doctor only temporarily while Bayreuth University looked into the accusations.

Guttenberg told jeering lawmakers in parliament last week that he 'did not deliberately cheat, but made serious errors'.

He said he had been overwhelmed by writing the work while starting a family and launching his political career and that he had been "arrogant" to believe he could juggle all at the same time.

Merkel stood by Guttenberg, saying a week ago: "I appointed Karl-Theodor zu Guttenberg as defense minister, I wasn't appointing an academic assistant."

But the scandal wouldn't go away. On Monday, Merkel received an open letter from some 23,000 doctoral students and others protesting her decision to keep him.

Guttenberg is a member of the Christian Social Union, the Bavaria-only sister party to Merkel's Christian Democratic Union.
While the CSU itself doesn't have to face voters this year, six of Germany's states are due to hold regional elections before the end of September. Three of those come in March — one of which, in the southwestern state of Baden-Wuerttemberg, offers a tough test for Merkel's center-right coalition.

Merkel had said that, despite the allegations, Guttenberg would campaign for her party ahead of those votes.

Polls taken early in the plagiarism scandal had suggested that Guttenberg remained popular with voters and that a majority wanted him to stay on.

"I was always ready to fight, but I have reached the limits of my strength," Guttenberg said Tuesday.
There was no immediate word on his replacement.