BANGKOK -- Booming loudspeakers, crowds of cheering protesters and the riot police on alert -- after a relative lull of more than two years, politics is back on the streets in Thailand.
Thousands of demonstrators cheered in a vacant Bangkok lot Saturday as speakers threatened to "overthrow" the government. But unlike in previous years, this time the protesters were members of Thailand's oldest political party, the Democrat Party, which has long had a reputation as the staid, well-mannered and intellectual voice of the Bangkok establishment and has been firmly dedicated to resolving differences inside Parliament, where the Democrats lead the opposition.
The threats by some of the Democrats' leaders to lead large-scale street demonstrations in the style of the Arab Spring -- stunning to many Thais because it seems so out of character for the party -- underlines the persistence of divisions in Thailand and raises the prospect of a return to the political turmoil that left more than 90 people dead on the streets of Bangkok in 2010.
"We are gathering up the masses, people left behind by this government," Sathit Wongnongtoey, a Democrat Party member of Parliament, told the crowd Saturday in front of a backdrop with a huge clenched fist. "We will rise up and fight."
The acrimony between the Democrats and the government of Prime Minister Yingluck Shinawatra centers on a number of legislative issues, chiefly an effort by the government to pass an amnesty law for those involved in the 2010 protests. The Democrats oppose the bill, saying it might also apply to those who insulted the monarchy or committed serious crimes.
But the broader conflict appears to stem from the Democrats' feeling of powerlessness in the face of the resurgence of Thaksin Shinawatra, Ms. Yingluck's older brother, who sets the broad policy lines for the government and the Pheu Thai Party despite living abroad since 2008 in self-imposed exile to escape corruption charges.
Abhisit Vejjajiva, a former prime minister who leads the Democrats, has been under relentless pressure since losing parliamentary elections two years ago. He was charged with murder in December for the deaths of protesters in 2010, when he was prime minister.
At Saturday's rally, Mr. Abhisit's speech was earthy and markedly more aggressive than his previous remarks. Other party leaders used coarse language to criticize the government, and the crowd repeatedly called for Ms. Yingluck's ouster with a vulgar chant. On Sunday, Ms. Yingluck held a meeting to call for national reconciliation, an effort the Democrats have refused to join.
Even inside Parliament, the Democrats have sought to portray themselves as street fighters, with one lawmaker shoving a security guard during a ruckus that a Thai newspaper described as a "disgrace."
"We want to awaken the masses," said Nipit Intarasombut, a lawmaker who leads the Democrats' radical faction that advocates aggressive street demonstrations.