The Supreme Court on Wednesday barred four incoming lawmakers from taking office, putting at risk the opposition’s newly won two-thirds legislative “super-majority.”

Responding to a legal challenge filed by supporters of the ruling socialist party, the Supreme Court blocked the four lawmakers from being taking their seats when the new National Assembly convenes Tuesday.

The ruling affects three opposition lawmakers and one socialist deputy, all from the sparsely populated state of Amazonas.

The opposition won a landslide victory in Dec. 6 legislative elections, taking control of congress for the first time in more than a decade. The coalition captured 112 of 167 seats, giving it by one seat a two-thirds majority that would allow it to rein in socialist President Nicolas Maduro.

Opposition leaders denounced Wednesday’s ruling and accused the government of using institutions to overturn the will of the people.

The socialist party has been in a frenzy of activity following the opposition’s win. The lame duck congress has approved new Supreme Court judges and made a series of other appointments, and Maduro has been using his expiring decree powers granted by congress to institute a series of new laws.

On Wednesday, Maduro appeared on national television to announce additional decrees, including raising taxes on high earners, but did not mention the court ruling.