The border between Serbia and Northern Kosovo is a joke.
The Serbs have erected barricades on the main roads, making it impossible for NATO troops from the Kosovo peacekeeping force (KFOR) to move.
The Serbs are demanding the withdrawal from the border posts of customs officials belonging to the mainly Albanian Kosovo government in Pristina, whose authority they do not recognise.
Meanwhile, the Serbs use a series of tortuous mountain tracks to cross back and forth between Southern Serbia and Northern Kosovo.
KFOR makes a half-hearted effort to control these, whilst issuing rather vague ultimatums to the Serbs for the removal of the barricades.
Confused? Me too. It is peaceful for now, but trouble has flared up in recent weeks and could do so again at any moment.
Of course the problem is that the Serbs do not consider "the border" to be a border. My impression, after three days in Serb-controlled Northern Kosovo, is that the ties between this region and "Serbia proper" (excuse the ugly phrase) are tighter than ever. Serbian flags fly everywhere.
The famous bridge in the divided town of Mitrovica is now blocked on the Serbian side by piles of rubble and stones, so that no vehicles can pass from the Albanian side. The (subsidised) train that runs every day between Northern Kosovo and Southern Serbia is packed.
European politicians are beginning to make noises about the need for Serbia to dismantle "the parallel structures" of government it maintains in Northern Kosovo.
In Belgrade I asked Oliver Ivanovic, Serbia's secretary of state for Kosovo, whether he had any intention of doing this.
"We don't see these as 'parallel structures', we see these as the only structures, because we do not recognise the independence of Kosovo" was his reply.
It is very difficult to see a solution to this problem.
Kosovo remains in a kind of limbo, recognised by the big Western powers, and some others, but forever blocked from full statehood by the Russian veto on the UN security council. At the same time, European countries are increasingly exasperated with Serbia.
So what about division? Serbia would get to keep the North of Kosovo, and would perhaps renounce control of the majority of the majority-Albanian Presevo Valley.
When I asked Serbia's President Boris Tadic about this in early 2010, he did not rule it out. But in the Balkans, redrawing borders along ethnic lines is tantamount to opening a can of worms.
So what does Ivanovic have to say about this? "Not something we would consider", was his reply.