Thailand Prime Minister Yingluck Shinawatra has appeared before the Constitutional Court in Bangkok. She is charged with abuse of power over her transfer of the national security chief in 2011.
Opponents say her decision benefited her political party.
Shinawatra could be forced to step down and some legal experts say her entire government may have to go.
The court’s decision is expected on Wednesday.
Six months of street protests aimed at toppling Yingluck have undermined her government. But she has clung onto power. The number of protesters has dwindled.
Tension is rising again, though. Both her supporters and anti-government protesters plan large rallies in or around Bangkok next week.