Earlier this month, the United States celebrated 60 years of diplomatic relations with Cambodia and marked the 15th anniversary of normalising ties with Vietnam.

You might, therefore, assume that the Americans would be chummier with Cambodia than Vietnam.

After all, they’ve been hooked up, diplomatically speaking, for four times as long. Cambodia has a Western-style, open-market economy and a multiparty political system that permits a degree of free speech.

In contrast, Vietnam’s economy remains command-driven, its media is entirely state-owned, and no political bodies can exist except the Communist Party.

But your assumption would be wrong. Washington strongly favours Vietnam, a country whose traditional enemy is China – which happens to be America’s strategic competitor in today’s world.

So, given that my enemy’s enemy is my friend, the US actively courts Hanoi. It has recently become Vietnam’s top foreign investor and is boosting military ties.

It has welcomed Vietnam’s leaders to the White House, and US presidents have twice visited Hanoi in the past decade. Washington also bends over backwards to mute its criticism of human rights abuses and the lack of democracy in Vietnam.

Not so when it comes to poor little Cambodia, however. The US has strangled this 60-year-old marriage, turning it into a relationship devoid of vibrancy and of any potential for mutual enrichment.

And it has done so because Cambodia accepted a loan from the US almost 40 years ago and has not yet repaid it.

Back in those far-off days, the Americans, in their zeal to defeat the Vietnamese communists – the very people they are now sucking up to – gave the brutal anti-communist regime of General Lon Nol aid worth $276,211,806 at a rate of 3 percent interest.

Modern-day Cambodia has long requested relief from this ancient loan, but Washington says no way, José. Pay up or stay out in the cold. America wants its pound of flesh, which it claims now amounts to $444 million with interest.

Cambodia has tried to be reasonable, suggesting lower interest rates or a debt swap similar to one given Vietnam in 2000.

But Washington says Cambodia should not qualify for debt forgiveness because it is not a heavily indebted country and lacks a balance of payments crisis. Furthermore, the proposed Cambodia Trade Act of 2010 forbids extending debt relief to Phnom Penh as a punishment for returning 20 refugee-seeking Uighers to China last December.

Two days after those Uighers were repatriated, China signed 14 deals with Cambodia worth more than $1 billion. Washington’s Shylockian avarice is playing right into Beijing’s hands.

As Ernest Bower, Southeast Asia director at Washington’s Centre for Strategic and International Studies, said: “Shortsighted US debt policy and narrowly-focused legislators are driving hopes for American engagement with Cambodia into the ground.”