phnom penh cambodia main opposition party boycott parliamentary vote strip detain leader immunity monday instead go kem sokha jail demand release one deputies say sunday kem sokha head cambodian national rescue party cnrp arrest week ago charge treason allegedly plot win power support unite state escalate crackdown critics prime minister hun sen independent media ahead general election next year two aid group run publisher cambodia daily shut week ago dispute cripple tax bill say suspend work account freeze parliament due vote whether remove immunity prosecution kem sokha get elect member parliament rule cambodian people party cpp majority mean motion certain pass anyway cnrp deputy leader mu sochua say parliament vote illegal accept demand kem sokha do anything wrong release say add members parliament would hold protest prison hold near border vietnam cpp spokesman sok eysan say opposition boycott would unconstitutional cpp enough vote strip kem sokha immunity anyway hun sen 65-year-old former khmer rouge commander rule cambodia 30 years say last week plan stay power another decade next year election expect tough electoral test western countries human right group raise doubt whether vote fair criticize kem sokha arrest china give back close ally hun sen. evidence present kem sokha far video record 2013 discuss strategy win power help unspecified americans lawyers dismiss evidence nonsense say discuss election strategy recent weeks hun sen also expel national democratic institute non-governmental organization promote democracy order 19 radio station air independent english-language cambodia daily shut last week give month pay 6.3 million tax demand japan relief cambodia world relief cambodia aid group finance paper publisher say account freeze would suspend build school teach english compute thousands pupils cambodian opposition party boycott parliament vote leader