In 2012, a little over a month after the Human Rights Party and Sam Rainsy Party won a combined 40 commune chief positions in local elections, the two groups met in Manila, finally agreeing on what had been bandied about for years: a united opposition party to challenge the power of Prime Minister Hun Sen.

Initially called the Cambodia Democratic Movement of National Rescue, the new party vowed to “unite all patriots and democrats”.

“Our nation is drowning in disaster. The country is under the dictatorship of a leader who serves only the interests of foreign invaders,” then-party leader Sam Rainsy said at a press conference in 2012.

Five years later, the opposition Cambodia National Rescue Party had come to hold more than 10 times as many commune chief seats – 489 out of a total of 1,646 – as well as nearly half of the seats in Cambodia’s National Assembly.

Now, however, it finds itself on the verge of dissolution – a dramatic turn of events less than a year before the national election. But one that observers say is the culmination of a long line of attempts by the government and ruling party to quell an unprecedented opposition challenge.

The CNRP’s current president, Kem Sokha, is in a prison near the Vietnam border on “treason” charges, and today the Supreme Court is likely to decide the fate of the long-ruling Cambodian People’s Party’s only viable electoral rival. According to the government, Sokha and the party have attempted to mount a “colour revolution” with the aid of the United States and European Union.

While these allegations are new in their ferocity, and seeming paranoia, they follow a five-year build up of pressure stemming from the CNRP’s surprising huge gains at the 2013 national elections and the CPP’s inability to hobble the opposition over the following years.

“The election showed that in a free and fair election, a unified CNRP had the potential to threaten the CPP’s hold on power. This is precisely why the government is now on the brink of abolishing the party outright,” Sebastian Strangio, author of Hun Sen’s Cambodia, said in an email.

Back in 2013, the newly formed party went into the national elections an underdog, bolstered by the return of Sam Rainsy from self-imposed exile just days before the electorate voted for the next government. Hun Sen and the CPP, meanwhile, approached the elections confident of political success, given it had won 90 seats out of 123 in the previous election in 2008.

Two opposition lawmakers are savagely beaten outside the National Assembly in 2015. Photo supplied

But after votes were counted, and amid accusations of election fraud, the CPP was left with just a 13-seat margin in the National Assembly, with the CNRP taking 55 parliamentary seats, nearly double what the two individual parties held in 2008.

Thus began a concerted effort to weaken the opposition, bit by bit.

“All along the goal has been the same: the consolidation of the CPP’s power, and the foreclosure of any opposition alternative. The difference is a matter of degree,” Strangio added.

These efforts included the piling on of legal charges against former party President Rainsy, who was again forced into self-exile in 2015 after a years-old arrest warrant was resurrected by the authorities.

Next, leaked phone conversations between Kem Sokha and an alleged mistress led to criminal charges after the then-deputy president failed to show up to court as a witness in an ensuing court case. For five months last year, Sokha was holed up in CNRP headquarters to avoid arrest.

Meanwhile, the rest of the party has faced a veritable political obstacle course as well.

Nearly two dozen activists were imprisoned for their alleged roles in a protest turned violent – dubbed an “insurrection” by the government – during the CNRP’s post-election demonstrations, and two lawmakers were brutally beaten by members of the Prime Minister’s Bodyguard Unit outside the National Assembly in 2015. During this latest crackdown, more than half of the CNRP’s parliamentarians have fled the country fearing intimidation and potential arrest.

Mu Sochua, a deputy president of the party who has also fled, said all attempts to subdue the CNRP after the 2013 elections had “totally failed”, pointing to this year’s commune election results. Though the CPP held onto two out of three communes, the CNRP won in more localities than any party to come before it. Both the CPP and the opposition have said the results are an indication of broad support.

“Mr Hun Sen was trying to buy time. And now he has run out of time,” she said.

Political commentator Ou Virak, founder of the Future Forum think tank, said that he doubted that dissolution of the party was the first objective of government, but said it had become a possibility after the premier failed to appease the electorate with reforms, and was subsequently unable to divide the CNRP.

“With the stakes still high, the chances of actually still allowing for an opposition victory was unlikely and pretty impossible,” he said.

CPP spokesman Sok Eysan, however, dismissed any attempts to link the current trials of the CNRP to next year’s elections, saying anyone doing so was wilfully ignoring the opposition’s infractions.

Opposition leader Kem Sokha is escorted by police officials following his midnight arrest in Phnom Penh in September. AFP

“This is their exaggeration to the national and international viewers, and it is also a trick to accuse us. But they do not talk about the CNRP’s crimes,” he said.

For observers, the recent crackdown has had one new element – direct attacks on the United States for allegedly orchestrating the so-called revolution, a claim vehemently denied by the embassy in Phnom Penh.

Nearly every government and military official in front of a microphone in recent months has railed against the US, doubling down on linking the CNRP to a foreign-backed conspiracy.

Sophal Ear, associate professor of diplomacy and world affairs at Occidental College in Los Angeles, highlighted external factors that have aided Hun Sen’s recent crackdown.

“It was not inevitable, but with the man [US President Donald Trump] in the White House, the backing of China, and the existing Prime Minister, it is where we are,” he said in an email, referring to Trump’s apparent disregard for democracy-building and human rights. “If [Hillary] Clinton was in the White House right now, I doubt this would happen.”

Though he called Cambodia “denuded of democracy”, with “autocracy” firmly in place, Ear said at some point he foresees a push-back.

“In fact, things will change again sooner or later, and something or someone’s going to have to give. It’s Newton’s third law of politics: For every action, there is an equal and opposite reaction,” he said.