Hun Sen is starting kicking back Sam Rainsy who has publicly suggested the one term PM, but Hun Sen seems have no ground and rationale to support his claim.
Firstly, Hun Sen is using his Premier to say something without respecting of national constitution. This is normal for Hun Sen leadership as he has acted from birth to death. In this case, many government leaders have severely implemented their task without respecting the national constitution, for example the deporting Tim Sakhorn to be tried by Vietnam's court withouth ensuring that Tim Sakhorn is legally having Khmer citizenship or not, this is an ugly violation of Cambodian national constitution and damning to all Cambodian citizens.
Secondly, for the sake of fair treatment, who fled the country during tension? The answer is everybody, for example, Sam Rainsy fled to France during immunity peeling off, Rannaridh fled to France during court's order, Hun Sen fled to Vietnam during coup d'etat in 1997...etc
Thirdthly, Hun Sen picked up this issue only creating discrimination and differentiating among Cambodian people who also love their motherland and want to share their willingness to save Cambodia.