Braun lost his seat in the 2005 federal elections. He was able to re-enter the Bundestag in 2009, winning the constituency of his home town of Gießen with a majority of 59,441 votes or 36.7%. After the election, he was again elected as deputy leader of the Hessian MPs. In the subsequent federal elections of 2013 and 2017 he was able to defend his seat.