Thais voted Sunday to choose legislators for the upper house of parliament in a test for Prime Minister Yingluck Shinawatra's beleaguered government.
The vote came a day after tens of thousands of protesters took to the streets of Bangkok to demand that the prime minister resign.
Sunday's voting went without disruptions, in contrast to the vote last month for the lower house. That election was boycotted by the opposition and eventually nullified by Thailand's Constitutional Court.
Should anti-government forces dominate the upper house, it will be easier to remove Ms. Yingluck if she is impeached. She has been charged with ignoring corruption within a government rice subsidy program that has cost the country billions of dollars.
Yingluck is scheduled to present her defense to Thailand's National Anti-Corruption Commission Monday.