When an ethnic Vietnamese crashed his motorcycle into an ethnic Khmer's car in Phnom Penh's Meanchey district last Saturday night, he was attacked by Khmers shouting the racially charged term for Vietnamese - "yuon" - and beaten to death.
That an ordinary traffic accident turned into a racist attack underlines the importance of managing ethnic fault lines in Cambodia - and the country's complex relationship with Vietnam, Cambodia's longtime regional rival, but also an ally of Prime Minister Hun Sen.
Tens of thousands of ethnic Vietnamese - some born in Cambodia, but others recent immigrants - have the right to vote in Cambodia. Mr Hun Sen needs their support in his rivalry with the opposition Cambodia National Rescue Party (CNRP), says Dr Sok Touch of the International Relations Institute in Phnom Penh. CNRP leader Sam Rainsy - who still refuses to accept the result of last July's general election - on the other hand, plays a divisive anti-Vietnam card.
The two parties pointed fingers at each other after last week's incident.
Mr Hun Sen, whose Cambodia People's Party (CPP) came to power in 1979 with the help of Vietnam, visited Hanoi in December last year as protesters back home demanded his resignation.
As this visit and a trip by the Premier to Japan showed, Cambodian foreign policy reflects the realities of domestic politics as well as its strategic interests.
Mr Hun Sen visited Japan in November last year and Japanese Premier Shinzo Abe reciprocated a month later with a visit to Phnom Penh. For Mr Hun Sen, courting Japan - a United States ally - is an indirect way of keeping on the right side of the US, says Dr Sok.
The trips have taken place at a time when Cambodia's relationship with China has cooled somewhat as Mr Hun Sen's hold on power has become less certain, although Chinese companies are pumping millions of dollars in investments into Cambodia, from malls to mines.
Sino-Cambodian ties were much better in July 2012 when Cambodia took Beijing's side over the issue of China's overlapping claims with several ASEAN states in the South China Sea, at an ASEAN foreign ministers' meeting in Phnom Penh.
Using its position as chair of the regional bloc, Cambodia blocked consensus on the mention of the South China Sea disputes in a joint statement. As a result, for the first time in its history, ASEAN was unable to issue a joint communique.
A year later, after the July general election which Mr Hun Sen's CPP won narrowly, China was among the first to congratulate him.
However, the narrow win and the continuing political turmoil in its aftermath as the opposition CNRP rejected the election results, refused to take its seats in Parliament and continued its protest against the results, raised questions on Mr Hun Sen's longevity in office.
The swing against the CPP - put down to a younger generation of voters less impressed by him and his government, widely seen as corrupt - came as a surprise to the well-entrenched party and showed that Mr Hun Sen was not invincible.
As the political stalemate dragged on, the Chinese were apparently displeased.
In December last year, China's state news agency Xinhua published an article rebuking Mr Hun Sen for failing to deal with the dispute.
It cited political analysts saying Mr Hun Sen should act swiftly to "restore his popularity". It also called for "serious and deep reforms" in Cambodia over the next five years.
China was now keeping Mr Hun Sen "at arm's length", wrote researchers Murray Hiebert and Phuong Nguyen of the Washington-based think-tank Centre for Strategic and International Studies in an article published by the Yale Global journal earlier this month.
Citing the Xinhua article, they wrote: "Chinese leaders probably will not give Hun Sen the cold shoulder any time soon, but they seem to be charting a middle course and slowly moving away from their past policy of wholeheartedly endorsing his government."
Other analysts are not so sure. On Feb 14, an article in the Phnom Penh Post newspaper quoted Australian historian and author Milton Osborne - a noted authority on Cambodia - as saying:
"We will need a great deal more evidence than is currently available to conclude that this relationship, which has so far served both parties well, is changing in a clear and important fashion."
And, important as Cambodia's ties with China are - China being Cambodia's most important economic partner - Mr Hun Sen has not allowed these to affect his country's ties with Vietnam. If anything, with China's increasing coolness to him, his relationship with Vietnam may become all the more important.
"As (an) immediate neighbour, Hun Sen has to keep Vietnam happy. After all, it was Hanoi who put him in power," Dr Ian Storey, a senior fellow at Singapore's Institute of Southeast Asian Studies, told The Sunday Times.
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