By Gabriel Partos
Balkan affairs analyst
Ratko Mladic was Mr Karadzic's right-hand man
The arrest of Radovan Karadzic by Serbia's security services has led to renewed speculation that his wartime military commander and fellow fugitive, General Ratko Mladic, could soon be apprehended.
The speculation was fuelled by remarks made by Rasim Ljajic, Serbia's minister for co-operation with the Hague tribunal, that security officials had come across the heavily disguised Mr Karadzic while trying to track down Gen Mladic.
Indeed, the capture of Mr Karadzic, rather than that of Gen Mladic, has stunned observers who have been following the 13-year hunt for the two wartime Bosnian Serb leaders, who were jointly indicted on charges of genocide, war crimes and crimes against humanity by the International Criminal Tribunal for the former Yugoslavia (ICTY) in The Hague 13 years ago.
The tribunal's prosecutors have been convinced for years that Gen Mladic is in hiding in Serbia, "within reach" of the Belgrade authorities.
By contrast, Mr Karadzic was believed to be literally on the run, frequently changing his hiding places as he criss-crossed the porous borders between the eastern, Serb-controlled, part of Bosnia-Hercegovina, his native Montenegro and Serbia itself.
Resolve or result
The tribunal's apparent certainty about Gen Mladic's whereabouts, based on information from Western intelligence agencies and its own investigators, has been shared by the European Union.
In May 2006, the EU froze negotiations with Serbia on a Stabilisation and Association Agreement - a preliminary deal intended to lead towards that country's eventual EU membership - after Belgrade failed to meet a deadline to deliver Gen Mladic to the ICTY.
Miroslav Labus, the pro-Western deputy prime minister in the conservative nationalist-led government of the time, handed in his resignation, claiming that the security forces had "searched for Mladic everywhere except where he was hiding".
The conviction that Gen Mladic's arrest is a matter of Serbian government resolve, rather than a question of tracking him down, persists to this day.
When the EU and Serbia finally signed and sealed their agreement in April, Brussels insisted that certain provisions would not be implemented until the fugitive general was handed over to the Hague tribunal.
The Serbian administration's policy therefore remains the key to Gen Mladic's capture.
It was partly to try to shift that policy that the EU was willing to forge closer links with Serbia in April, and the elections in May helped President Boris Tadic's firmly pro-European Democratic Party to victory.
Since then the new government, under Prime Minister Mirko Cvetkovic, has acted with remarkable speed.
Mr Karadzic's arrest was announced on Monday, two weeks after the Cvetkovic administration was sworn in.
So does Mr Karadzic's arrest mean that Gen Mladic's capture could be just around the corner?
Many Bosniaks hope the arrest of Mladic may not be far off
By apprehending the former Bosnian Serb leader, the Serbian authorities have broken a taboo in Belgrade's policy in recent years, and as a result it may now become easier to detain Gen Mladic as well.
The fact that the Karadzic arrest has provoked little initial opposition from hard-line nationalists will also militate in favour of arresting the general.
However, there is no exact equivalence between the two cases.
Even at the height of his success during the Bosnian war, Mr Karadzic was a divisive politician who did not enjoy universal popularity among hardline nationalists, let alone all Serbs.
He was often at loggerheads with the late Slobodan Milosevic, the president of Serbia at the time, and, unlike Gen Mladic, who lived openly in Serbia until after Mr Milosevic was ousted from power at the end of 2000, Mr Karadzic chose to go into hiding.
By contrast, Gen Mladic is respected by many Serbs as a simple, straightforward soldier whom they view as the main protector of fellow Serbs during the war, and even today relatively few of them share the international revulsion that led to his indictment for the three-and-a-half-year siege of Sarajevo and the slaughter of nearly 8,000 Bosniak men and boys at Srebrenica in 1995.
Besides, Gen Mladic, who was drawing an army pension from Belgrade until the end of 2005, has been enjoying the protection of a network of ex-officers in Serbia.
Last but not least, he is likely to be armed, although his boast in the 1990s, when he still had a retinue of bodyguards, that those who tried to capture him would be "bathed in blood" now has a hollow ring to it.
Although capturing Gen Mladic would be fraught with difficulties, that prospect has come a step closer with Mr Karadzic's arrest.
Yet there is one more factor that could delay attempts to detain the general.
Once he is sent to The Hague, Belgrade will have few bargaining chips left in its negotiations with Brussels.
It is possible therefore, that the authorities may wait before making that move until there is a chance that it will lead to the EU granting Serbia the status of a candidate for EU membership - a goal Belgrade would like to see achieved by the end of this year or early 2009.