German chancellor Angela Merkel said on Sunday she would like to continue her ruling coalition with the liberal party after elections in the fall and warned that the alternative might be an entirely left-wing government.

In an interview with ARD television, the conservative leader, who has been in power since 2005, said she was “convinced” her Free Democrat coalition partners would cross the 5-percent threshold in September’s election and stay in coalition with the Christian Democrats. Recent surveys put the liberals’ support at just 5 percent.

Merkel’s finance minister Wolfgang Schäuble, a fiscal hawk, similarly told weekly Der Spiegel in May that the government would defend its majority in the lower chamber of parliament. He even ruled out a “grand coalition” with the Social Democrats while Merkel seemed only reluctant to entertain the possibility.

“If the right doesn’t win a majority,” said Schäuble, the Social Democrats and Green party should “repeat what they did in North Rhine-Westphalia,” Germany’s most populous state where the two parties fell short of a legislative majority in a state election three years ago but were able to form a government with the backing of the far-left Die Linke.

Merkel also suggested that was the most likely outcome if her conservative CDU failed to win reelection in coalition with the liberals. It seemed a warning to centrist voters who might otherwise consider supporting the Social Democrats or Green party, once a far-left pacifist movement that has reinvented itself as a cosmopolitan alternative for socially liberal voters. “If you want me to remain chancellor,” she said, “you simply must vote CDU.”

Even if Die Linke looks likely to lose up to half of its seats, it might get enough votes to help the Social Democrats and Greens win a majority. In a Forsa poll released last week, the two parties got 22 and 15 percent support respectively, compared to 41 percent for Merkel’s Christian Democrats.

Last month, Merkel’s government agreed to a three year fiscal consolidation plan that envisages a modest budget surplus as early as 2015. In the interview, she promised to stay the course if reelected.