Germany's presidential election has gone to a third ballot after Chancellor Angela Merkel's candidate failed to secure an absolute majority in the first and second rounds.
The June 30 election in a special assembly has been pegged as a test for the chancellor's troubled coalition.
On paper, the center-right coalition had enough of a majority to secure victory for its candidate Christian Wulff. But he fell 20 votes short of the 623 needed to win the first round, and eight votes short in the second.
Wulff's nearest rival is Joachim Gauck, a former East German dissident and pastor. He won 499 votes in the first round, dropping nine in the next round.
A third opposition candidate, Lucrezia Jochimsen, won a little over 120 votes in each ballot.
For the third ballot, candidates need only a simple majority to win -- half of the votes cast, plus one. That ballot is to be held shortly.
The vote is to replace Horst Koehler, who stepped down from the post last month -- just one year into his second term -- citing public criticism over an interview he gave on Germany's military role abroad.
Bundestag President Norbert Lammert, speaking ahead of today's vote, said the move left many people mystified. But he told those assembled to elect Koehler's successor.
"This Federal Assembly is taking place because the federation's president has resigned from office, effective immediately," Lammert said.
"This is an unprecedented event in the history of the Federal Republic and in the democratic history of our country. We must respect this decision and the reasons behind it, even though many of us still cannot really understand it."
The election of a new president -- a largely symbolic role -- is held by secret ballot in a special assembly composed of 1,244 representatives, half of whom are lawmakers and the other half state parliamentary nominees.
Analysts say a loss for Merkel's nominee, state governor Wulff, could be disastrous for the Chancellor's political career as support for her center-right coalition hits a 10-year low.
Wulff faces strong opposition from rival candidate Gauck, a widely admired former East German human rights activist nominated by the left-wing Social Democrats and Greens.
Polls show that Gauck -- who for a decade ran a commission investigating the role of East Germany's Stasi secret police -- has greater popular support than Wulff, prompting media speculation about a possible upset.
Analysts say Merkel's coalition is likely to be judged by the number of ballots it will take to establish a clear winner.
Since it took office in October it has been plagued by incessant political squabbling and forced to push through new unpopular austerity measures in the wake of the eurozone debt crisis.
In Germany, the presidency is held for five years.written by Kristin Deasy, with agency reports