An upstart Thai political party has delivered a shocking blow to a royalist establishment that has suppressed democracy over the past two decades. Now the question is whether it can implement real change without a fight.

Pita Limjaroenrat, the 42-year-old Harvard-educated leader of Move Forward, staked his claim to becoming Thailand’s prime minister after his party won the most seats and total votes in Sunday’s election. The party was by far the most ideological in a field of politicians pledging populist handouts, standing alone among major groups in calling for changes to a law that restricts criticism of the nation’s powerful monarchy.

Addressing reporters after the win, Pita vowed not to compromise in the push to change Article 112, a law known as lese-majeste that can put offenders behind bars for as many as 15 years if they’re convicted of insulting 70-year-old King Maha Vajiralongkorn or several other top royals.