Thai reformist Pita Limjaroenrat's bid to be nominated prime minister has ended, prompting outrage from his supporters after he won May's election.
The 42-year-old was first dramatically suspended from parliament by the constitutional court, forcing him to leave the debating chamber.
The Move Forward party leader had swept to victory in the general election as voters rejected years of military rule.
But to seal his victory, he needed the approval of parliament - which he failed to secure last week, plunging the country into political limbo.
The constitutional court must now decide whether he should be disqualified from parliament for owning shares in a long-defunct media company.
Mr Pita, a Harvard graduate and former tech executive, won on the promise of major reforms, including a pledge to amend lese-majeste, Thailand's strict royal defamation laws, pitting him against the unelected senate and other conservatives who say he poses a threat to the monarchy.