On 15 August, Hong Sok Hour, a long-serving Cambodian opposition senator, was arrested by police and charged with treason. Such are the wages of those opposing the country's long-serving prime minister, Hun Sen. In typical fashion, the Prime Minister foreshadowed the arrest during a speech at a graduation ceremony two days prior.

After Sok Hour posted a fake section of a 1979 border treaty with Vietnam on Facebook, implying that the Government had ceded territory to its hated eastern neighbour, the Prime Minister called for his arrest. 'This is treason; I can say it like this,' Prime Minister Hun Sen said.

The arrest of Hong Sok Hour, despite the immunity he technically enjoys as a member of the senate, formed the exclamation point on a crackdown which has unfolded over recent weeks in Cambodia. It follows the 21 July conviction and jailing of 11 members of the opposition Cambodia National Rescue Party (CNRP) on the charge of 'insurrection' resulting from a minor clash with security forces in July 2014. Hun Sen has since warned of further arrests of opposition lawmakers and described CNRP President and long-time nemesis Sam Rainsy as the leader of 'a gang of thieves destroying the stability of this country'.

In most respects the crackdown is politics-as-usual for 63 year-old Hun Sen, whose bursting arsenal of threats, manipulations and personal charisma has kept him at the apex of the country's politics for three decades (and counting). It also appears to have spelled an end, at least for now, to the period of relative openness which was established under the rubric of the 'culture of dialogue', a political pact agreed between Hun Sen and Sam Rainsy in the tense aftermath of the July 2013 national elections. 

The elections surprised most observers of Cambodian politics. Despite an immense advantage in resources, the Cambodian People's Party (CPP), which has ruled the country since the fall of the Khmer Rouge regime in 1979, saw its parliamentary majority plummet from 90 seats in the 123-seat National Assembly to just 68, its worst result since 1998. The CNRP won the remaining 55 seats, tapping a deep reservoir of discontent over corruption, land-grabs and deforestation which has escalated under Hun Sen despite more than a decade of strong economic growth.

In fact, Sam Rainsy and his deputy Kem Sokha claimed they would have won the election outright were it not widespread electoral fraud. They launched a boycott of the new parliament, pressing their claims with large public rallies in late 2013 and early 2014. 

But over the following months, menaced by state security forces, the CNRP was forced to jettison its main post-election demands, which included Hun Sen's resignation and a UN-backed probe into the conduct of the election. Finally, in July 2014, the two parties reached a deal for the CNRP to end its parliamentary boycott. The Government agreed to rewrite electoral laws and reform the CPP-dominated National Election Committee, while the CNRP would get a license for its own television station. Rainsy and Hun Sen also proclaimed the 'culture of dialogue', agreeing that they would end the vicious insults which had flown between them during the post-election period.

As a strategy, the 'culture of dialogue' defies easy categorisation. Rainsy has trumpeted it as a means of transcending old destructive patterns in Cambodian politics (and presumably of boosting his own chances of victory in 2018). So far it has given Cambodia-watchers some interesting tableaux: in July, social media went berserk when a selfie emerged of the two rivals and their families enjoying dinner at a Phnom Penh hotel.

In this climate of relative openness, more radical elements of the CNRP also took the opportunity to launch a vocal campaign to address alleged Vietnamese encroachments along parts of the frontier. This has long been a 'red line' issue for Hun Sen, whose party was placed in power by the Vietnamese in 1979. At first Hun Sen appeared on the back foot as CNRP activists trooped down to 'inspect' the placement of border markers, clashing on one occasion with Vietnamese villagers and security forces. On 16 July the premier even said it was possible that some border markers could have been placed incorrectly – an unprecedented admission.

But on the whole, the 'culture of dialogue' seems to have done little to curb the political instincts of Hun Sen, whose long career stands as a testament to the primacy, in Cambodia's troubled history, of hard power over soft principles. And so, as Cambodia heads towards important local elections in early 2017, Hun Sen has returned to the political offensive.

Last month the CPP-dominated parliament rammed through a controversial bill regulating Cambodia's sprawling non-government sector, which, if history is any indication, will be used to smother dissenting opinion. The CPP sees the political opposition and independent NGOs as more or less synonymous.

Meanwhile, to neutralise claims that he is a Vietnamese stooge, Hun Sen has simply adopted the border issue as his own, sending several diplomatic notes to Hanoi protesting possible encroachments while threatening to arrest anyone else criticising the Government's border policy.

Whether the current crackdown serves the Prime Minister's ultimate aim – victory for the CPP at the elections of 2017 and 2018 – is too soon to say; the well of discontent in Cambodia runs deep. But it stands as a reminder that the continuities in Cambodian politics are in many ways as compelling as the recent changes. It's an indication, too, that under Hun Sen's command, the political pendulum only swings so far in one direction before it comes hurtling back.

Photo courtesy of Flickr user Prachatai.