Cautious in the face of mounting political danger, Prime Minister Hun Sen watched for three months as the opposition CNRP advanced a hostile campaign accusing his government of surrendering swaths of Cambodian territory to Vietnam.
His silence soon gave way to unprecedented offers to rectify border posts improperly placed inside Cambodia’s territory, and requests to the U.N. and foreign countries for maps of Cambodia to check against the one being used by the government.
Then, two days after CNRP lawmaker Real Camerin led some 2,500 people to inspect a reported Vietnamese incursion in Svay Rieng province, 11 opposition activists were suddenly sentenced to prison on charges of insurrection.
From Europe, Mr. Rainsy interpreted the decision as a message to the CNRP to end its border campaign, but five days later accused Mr. Hun Sen’s government of standing by as Vietnam annexed the land Mr. Camerin visited.
If the activists’ sentences failed to sway Mr. Rainsy, however, the arrest of opposition Senator Hong Sok Hour—a close friend and fellow French citizen—on Saturday proved more persuasive, with Mr. Rainsy pledging Monday to stop attacking the CPP on the border.
“If we know they are sensitive, we won’t poke their waists, we will look for a [new] way. When we know they are sensitive, we have to be careful and comfort them somehow to find a result for the nation,” Mr. Rainsy said to reporters after visiting the CNRP’s jailed activists.
“If a job is proceeding, and we talk about it publicly and openly, sometimes there are things that are right and things that are wrong, and [it is like] mixing mud with fish paste,” he said. “If we work together…it is a more effective way.”
Ou Virak, a political consultant and founder of the Future Forum think tank, said that Mr. Hun Sen had delivered a clear message to Mr. Rainsy that further politicking on the border would only lead to more of his wrath.
“Basically, the CPP has recently been trying to remove the one major sensitive issue that has haunted them, and they have been doing this by showing they are arresting illegal Vietnamese immigrants and sending them back,” Mr. Virak said.
“It has been very clear in local media, in the CPP-affiliated press, that they are going after the Vietnamese, and taking on the rhetoric of the opposition in order to stop this sensitive political issue,” he said.
“And thousands of people going to the border is the worst case scenario for this,” he added. “Hun Sen wanted to make a statement about this.”
Mr. Rainsy has said such arrests are not damaging to his “culture of dialogue” with Mr. Hun Sen, which began after last year’s political deal and was meant to foster an atmosphere free of threats and violence leading up to the 2018 national election.
Kem Ley, a political analyst who recently helped create the Grassroots Democracy Party as an alternative to the two main parties, said Mr. Rainsy’s helplessness in the face of political arrests exposed the futility of his “dialogue” with the prime minister.
“From the beginning until now, the culture of dialogue has been useless. A culture of dialogue should have clear mechanisms to solve issues, but the CNRP only do not want to fight the government anymore,” he said.
Mr. Ley said Mr. Hun Sen was trying to ramrod a cautious Mr. Rainsy into submission.
“The main purpose of the government is to end freedom of expression on the border issue, and to legitimize the border postings, and they want the opposition to support what they have done so far in talks with Vietnam,” Mr. Ley said.
“This is the CPP’s political culture,” he said.
Yet Mr. Rainsy said by telephone Monday that the arrests of Mr. Sok Hour and the other activists were symbols of the opposition’s recent success in damaging the CPP, and said the culture of dialogue has limited the blowback.
“The situation would be much worse now without the culture of dialogue, because thanks to the culture of dialogue there has been damage control and there are still some lines of communication,” Mr. Rainsy said. “With the culture of dialogue, we can still control the situation.”
“The CPP is kind of desperate. They are panicking. This wave of arrests shows they are panicking and losing ground. It does not show strength. If you were confident in your popularity, you would not do that,” the opposition leader said.
“Hun Sen now is not happy—angry and frustrated—by the border issue,” he added. “When we create the conditions conducive to changes in his mind, we can find common ground on issues like the border.”
CPP spokesman Sok Eysan said he was grateful that Mr. Rainsy now acknowledged he was provoking the government with the border campaign, but said he doubted the opposition leader’s sincerity in saying he would now end it.
“He seems to have woken up, because previously he never talked about poking the government’s waist, and now he has said it, therefore he knows it was his error. His words ‘poke the waist’ have a lot of meaning,” Mr. Eysan said.
“We will wait and see whether he can do it [keep his word] or not. I do not believe it.”