Updated

Germany's vice chancellor is trying to rally his struggling pro-market party as it gears up for September elections — portraying it as the only political force that will prevent tax hikes and a staunch defender of Berlin's tough approach to the European debt crisis.

Polls show Philipp Roesler's Free Democratic Party short of the 5 percent support needed to win parliamentary seats — a complicating factor in conservative Chancellor Angela Merkel's quest for a third term. But Roesler, who long looked likely to lose his job as party leader, has been strengthened by an unexpectedly strong performance in a January state election.

Roesler is running unopposed for re-election as leader at a convention Saturday. He said: "if we stand together, if we stick to our guns, we will be successful."