Opposition infighting and confusion over competing strategies have markedly slowed the drive to topple Yugoslav President Slobodan Milosevic since a series of mass rallies spawned by the Kosovo war put his government on the defensive over the summer.

One sign of Milosevic's belief in his survival emerged last week, when his spokesman withdrew an offer of early elections that had been extended as a way to defuse what appeared to be a swelling wave of criticism. The shift was seen as a sign that Milosevic believes he can ride out the postwar discontent without concessions to the political opposition, which is demanding a change in leadership for Yugoslavia and its dominant republic, Serbia.

A portion of the opposition will try to regain momentum with rallies on Tuesday in 20 cities, including Belgrade, the Yugoslav and Serbian capital.

The turnout and fervor exhibited will be seen as a gauge of public stamina, which many observers think has been sapped.

The war-weary country, with Kosovo effectively cut off, seems ripe for rebellion. Displaced people crowd shelters and complain of government indifference. International trade sanctions have exacerbated deep economic problems. Prices are rising, fuel is in short supply, and jobs are scarce. Reconstruction after the war has been limited to patchwork repair of roads, bridges and housing. Without foreign help and a reopening to world trade, recovery is impossible, economists say.

But for people hoping for quick change, opposition wrangling is an unwelcome diversion. Polls show that few expect Milosevic's exit soon, and some fear violence. Washington, eager for Milosevic's ouster, is quietly lobbying for opposition unity but has gotten nowhere.

"Our opposition is awful," said Aleksa Djilas, an independent political observer. "It's the main reason Milosevic is still in power."

"They want us to go out into the streets, but I don't feel like putting my head out to be hit to benefit politicians who just stand for themselves," said Dragan Savic, an auto repairman who took part in early demonstrations but plans to stay home from now on. "I have enough problems just to survive."

Many analysts agree that before a credible challenge to Milosevic can be mounted, one key opposition rivalry must be resolved--that between Zoran Djindjic and Vuk Draskovic. Djindjic heads the Alliance for Change, a coalition of opposition parties that wants Milosevic to resign in favor of a government of economic experts that would form an interim administration pending new elections. The alliance is spearheading Tuesday's rallies.

Draskovic leads the Serbian Renewal Movement, which alternately has opposed Milosevic and formed part of his ruling coalition. Draskovic wants immediate elections without the government of experts as an interim step and is staying away from Tuesday's demonstrations.

Djindjic, a butch-cut philosopher and former student activist, and Draskovic, a bearded novelist, despise each other. The pair appeared on the same platform in August, during the last big anti-Milosevic rally in Belgrade. Since then, they have been at each other's throats.

Aides to Djindjic criticize Draskovic for alleged corruption in the Belgrade city government he controls and for cozying up to Milosevic. Draskovic's associates fault Djindjic for everything from speaking broken English to a lack of patriotism for fleeing Serbia during the Kosovo war.

Djindjic says the demonstrations are the first in a series of protests, sit-ins and road blockades meant to undermine Milosevic. "The goal is to show that he cannot govern," Djindjic said in an interview.

Djindjic and his alliance back Dragoslav Avramovic, a former head of the Central Bank, as their candidate to head a post-Milosevic government. Avramovic worked wonders in pulling Yugoslavia out of hyperinflation in the early 1990s and is widely regarded as the country's most popular politician. But even Avramovic, 77, has doubts about his candidacy.

"Every morning I wake up and wonder, do I need this?" he said the other day.

Tuesday's turnout will be scrutinized as a measure of Djindjic's ability to draw a crowd. A light turnout will inevitably bring calls for Djindjic to bow to Draskovic.

Draskovic's followers insist that Djindjic is unelectable and that only the Serbian Renewal Movement is capable of taking on Milosevic. Last week, a delegation of Draskovic's aides traveled to Montenegro--Serbia's disaffected partner in the Yugoslav federation--to try to persuade U.S. State Department officials to support his early election plan. According to American officials, Washington was noncommittal and stressed the importance of opposition unity.

"Only Draskovic can win; he's got the charisma and the party," said an aide in a typical partisan evaluation. If Djindjic falters, Draskovic will call his followers into the streets with the aim of forcing elections, to be conducted under strict rules, including international supervision.

The divisions and stumbling do not mean Milosevic has let down his guard. On the contrary, he spares little effort to undermine the opposition. Last Friday, the Yugoslav government opened a new barge-supported bridge across the Danube River in Novi Sad at the same time that Alliance for Change had scheduled a convention in the city. Novi Sad's bridges were destroyed by NATO aircraft during the war, and residents have had to use ferries to cross the river.

Workers at the site said they were ordered to open the span to pedestrian traffic early, even though railings were not yet in place and seams in the concrete roadbed were still being filled with tar. "They wanted to attract the public away from alliance's rally," said one worker.