President Slobodan Milosevic appears able to count on the loyalty of his core security forces if he chooses to unleash a violent crackdown in the face of opposition claims to have won Sunday's Yugoslav elections.
Official results are not expected until today at the earliest, but Western diplomats say Mr Milosevic may be considering using force to crush opposition street protests.
His ultra-loyal Interior Ministry (MUP) special police force is an army in all but name, and the Yugoslav Army (VJ) has been gradually purged of independent-minded generals.
The large NATO peacekeeping forces in Bosnia and the southern province of Kosovo, although formidably armed, have no contingency plans for intervention in Serbia, or in Montenegro, should Mr Milosevic move against the pro-Western junior partner in the Yugoslav Federation.
That small, coastal republic would have to rely on its own well-armed police force if Mr Milosevic tried to turn the VJ 2nd Army against its government, which fears he could do just that.
Western officials, convinced Mr Milosevic will not allow Dr Vojislav Kostunica to take power whatever the real count, have raised the possibility of a "Ceausescu scenario", in which dissident lieutenants might topple him, like the late Romanian dictator.
A former Yugoslav armed forces chief, Gen Momcilo Perisic, who has joined the opposition, appealed to the army and police yesterday to "fulfil their constitutional duty and protect the people's will". But Western experts said the security forces have no record of disobedience to Mr Milosevic.
Prior to Sunday's polling, diplomats said the student-based resistance movement Otpor would act as an "infantry" to get out the opposition vote, but it is an unarmed infantry.
Nearly half of the 85,000-strong VJ is made up of low-paid conscripts with no special allegiance to the regime, but they inhabit the lower ranks.
Chief of Staff Nebojsa Pavkovic is a firm loyalist.
"You have a command and certain units which are more loyal than anything that Milosevic has had since he came to power," said Mr James Gow, a Balkans expert at King's College War Studies Department in London.
"The people at the top are his people and he can rely on them to do such things as necessary."
Mr Gow said there were undoubtedly those among the army's lower ranks who could switch allegiance to Dr Kostunica if he won the poll, but Mr Milosevic had the full backing of the MUP and top VJ command.
"In this context, the MUP is more important and it is almost entirely reliable," he said.
Mr Milosevic relied on his heavily armed paramilitary police for a lot of the fighting against Croatia during its 199195 independence war, and the MUP carried out most of the repression in Kosovo.
It has armoured vehicles, automatic weapons, anti-tank missiles, mortars and helicopters and it numbers around 100,000.
Mr Chris Bennett, an analyst at the Brussels-based European Stability Initiative think-tank, said "a lot of parts of the army are frustrated and dissatisfied. But the army just isn't the institution it once was. The former JNA (Yugoslav national army) has been destroyed in purges over the years and the army is now considerably weaker than we might think."
The officer corps of the Serbdominated but multi-ethnic JNA was "cleansed" as former republics broke away from Belgrade's control. If Mr Milosevic chose to launch a bloody crackdown on opposition protests against the election result, he would do so through the MUP rather than the army, Mr Bennett said.
"He has invested more in the Interior Ministry and he uses that to control the country, rather than the army."