Two German plaintiffs trying to stop the euro region’s future permanent bailout fund said they expect the nation’s highest court to set limits on Germany’s liabilities and tie its approval to popular consent.

“I think the judges once again will harden the budgetary sovereignty rights and somehow hedge the financial burdens for Germany,” economist Joachim Starbatty said on Phoenix public television.

Former German Justice Minister Herta Daeubler-Gmelin, another plaintiff, said she hopes that shifting rights away from Germany’s lower house of parliament will only be allowed after the country’s voters have approved it or the European Parliament has been given more competencies.

The Federal Constitutional Court in Karlsruhe, Germany, is due to rule on Sept. 12 on the plaintiffs’ challenge to the European Stability Mechanism. The 500 billion-euro ($639 billion) ESM, designed to bail out indebted euro-area member states, is a cornerstone of efforts to save the currency.