Jumping in with some info here:

From the Financial Times:

Belarus used to receive Russian crude oil duty free and resold it in the form of refined products at a hefty profit. It was supposed to hand on 85 per cent of the profit to Moscow but had long stopped doing so. (...)On January 1, Russia introduced a standard $180 export duty on its crude oil, depriving Mr Lukashenko of an annual profit of nearly $2bn.

Whatever the cause, this latest interruption of Russian energy supplies to Europe in just over a year is likely to dent further its reputation as a reliable supplier.

So we are told that Belarus has been stealing $2bn from Russia (but that concept of "stealing" disappears as the FT chooses to call "profit" what would be designated as "loot" anywhere else), but that Russia is nevertheless wrong to take action.
So, let's see...

• the sanctity of contract (so widely used as an argument against Russia in the case of the Sakhalin PSA) would suggest that Russia has a point and that Belarus should not be able to get away with theft. Europe, as the purchaser of stolen goods, might also want to feel slightly embarrassed;
• Belarus was being subsidized by Russia, and Russia is simply trying to take away these subsidies. Isn't it what the freemarketeers types always argue for? That subsidies are distorting, create perverse incentives, and should be eliminated to allow for a proper allocation of resources? Belarus is currently wasting the cheap oil it gets from Russia. With real prices, it will use less (which will leave more for Europe to buy, btw)
• Belarus is the country actually using its physical control over pipelines to blackmail Russia. If anyone is using the pipeline/energy weapon, it is Belarus, not Russia. But no, the blame will be put on Russia anyway, because, frankly, who cares about Belarus?
• there is a market solution: buy Russian oil at the Russia-Belarus border, and deal with Belarus transit (and their own consumption) ourselves, on market conditions or whatever else we manage to do. I'm pretty sure Russia would be extremely happy to do that. (Same with Ukrainian gas, btw);
• alternatively, we're "free" not to use Russian oil and find other suppliers or, better, not use oil. Isn't it what freemarketeers say about the poor and others when the conditions to purchasing a good become inacceptable - do away with it?

But of course, we cannot "do away" with oil, it's not even considered, so we have to bludgeon Russia and others to keep on supplying us.

More here: http://www.dailykos.com/story/2007/1/9/94633/38095