The decision all but kills off any hope of the election-winning party from leading the next government.

The move on Wednesday all but kills off any hope of the progressive party leading the next government and paves the way for the legislature to hold a vote on another candidate for prime minister as soon as this week.

Thailand has been under a caretaker government for five months. Its biggest parties in parliament have been unable to form a government after Pita Limjaroenrat, leader of the anti-establishment Move Forward, was rejected as prime minister by legislators allied with the royalist military.

In its decision, the court said it declined to accept the case because it was lodged by a group of more than 20 individuals that did not include the prime ministerial candidate himself.

“Their rights were not violated and they did not have the rights to file the complaint,” it said of the petitioners, in what was a unanimous decision.