German President Horst Koehler hopes to secure a second five-year term on Saturday in an unusually tight parliamentary vote just months before the country chooses a new government, Associated Press reported. Koehler, 66, is a member of Chancellor Angela Merkel's conservative Christian Democrats and a former head of the International Monetary Fund. Polls show that he has become one of Germany's most popular politicians since taking the largely ceremonial presidency, but his re-election is not assured. Gesine Schwan, 66, a center-left Social Democrat and former university professor, is challenging Koehler in a rerun of the 2004 presidential vote. She hopes to become the first female head of state. A special 1,224-member assembly crammed into Berlin's glass-domed Reichstag parliament building to make the choice. The presidency, which carries moral authority but little real power, is supposed to be above the political fray.