Over the course of the second Palestinian intifada, this city became the West Bank's capital for car thefts, kidnappings, and suicide bombers.

Now, with 300 security officers from the Palestinian Authority (PA) freshly deployed around Nablus, the city has become a testing ground for an embattled Palestinian president, Mahmoud Abbas.

Analysts say that Mr. Abbas must prove to his American and Israeli supporters that he has the power to control this defiant city, which could go the way of the Gaza Strip if central government control is not exerted. Abbas's Fatah Party was routed from Gaza in a violent coup led by its rival, the Islamic militant group Hamas.

On Sunday, as PA policemen began looking for stolen cars and armed militants at checkpoints around Nablus, US Secretary of State Condoleezza Rice met with her Israeli counterparts in Jerusalem to resolve issues getting in the way of bringing Israelis and Palestinians to the table for a Middle East peace conference in Annapolis, Md., later this year.

Israel and the Palestinians are still at odds over a joint document for the conference, which would serve as a launching pad for negotiations on core issues such as borders and the fate of Jerusalem and millions of Palestinian refugees.

Much of the progress at the peace table is expected to be predicated on Palestinian police in Nablus going after the Al Aqsa Martyrs Brigade, the insubordinate foot soldiers of Abbas's own party.

"For the Americans and the Israelis, it is important because it makes the partner more credible instead of just being a paper tiger. How can the PA sit at a table and negotiate big issues if it can't solve small issues like an assertion of its own power?" asks Mohammed Dajani, a professor of political science at Al Quds University in Jerusalem.

"This is an attempt to give the PA some stature and some respect among Palestinians by saying it can enforce its sovereignty. The rule of the gangs was beginning to grow here as it was in Gaza. It was spreading to the West Bank. Unless the PA reasserts their presence and authority within society, then everyone can buy a gun and establish their own fiefdoms," he says.

And so, after being banned by Israel for most of the intifada, PA security officers armed with AK-47 machine guns in Nablus have returned to the streets in their green patrol jeeps. Over the weekend, Israeli forces at the Nablus perimeter let in hundreds of reinforcements fresh from European-run training courses in the West Bank city of Jericho.

Even though the Palestinian police don't have the last word on security in Nablus like in the 1990s – Israel's army is reserving the right to chase after fugitive militants in the city when it sees fit – expectations are high among residents who want to see police officers arrest those responsible for frequent shooting sprees and carjackings.

"The big challenge is Nablus. We have taken Nablus as a model. And we would like to perform," says Intelligence Chief Tawfiq Tirawi, considered the top PA security chief in the West Bank. "If we are capable of consolidating law and order in Nablus, then the rest of the West Bank is a piece of cake."

To do that, the police will have to patrol the stone alleyways of Nablus's Old City, where young people boast of drug use and plain-clothed militants mock PA security forces.

Despite the talk of a crackdown, Bashar Aqub strolls an empty arch-covered corridor with a pistol in a holster. Wearing a Puma sweater and speaking openly about his membership in the Al Aqsa Martyrs Brigade, he brags that the PA police won't dare enter the Old City.

"They don't impress me," he says. "The PA can never come to the Old City to catch us. The PA can only come to the Old City with our permission."

He insists that his group of militants are "clean" of criminal activity and has been subject to a smear campaign by the Palestinian Authority. "This is a legal weapon," he says, about his gun. "I will not give it up for anyone."

With the help of European governments and with some $86 million from the US, the Palestinians aim to remake their security forces into a professional outfit. Two weeks ago, a military academy opened where officers will study conflict management, Hebrew, and information technology.

A Western military official with contacts in the PA said bringing Nablus under the sole control of PA forces isn't a mission that will be completed overnight. "It depends how you define success," the source said.

Abbas has said repeatedly that he wants to establish "one authority and one gun."

But as the central government withered in the turmoil of the Palestinian uprising, Nablus came under the control of young gang members who enforced their own law while the government fell into disrepair. And, even though Hamas is not a power broker here as it is in the streets of Gaza, branches of the Al Aqsa brigades wage turf wars that exacerbate the fears of residents already scared about Israeli army incursions.

The vacuum of authority touched Awni Kaldoun when his 14-year-old son was abducted last month outside his apartment by kidnappers hoping to pressure the moneychanger to pay an outstanding debt. Only after a week-long ordeal was the teenager returned, though Mr. Kaldoun says the Palestinian police had no part in the release.

"We dealt with it in terms of tribal law. The police were unable to deal with it," he explains. "I submitted other complaints, and no one was arrested."

He said he was skeptical about the new deployment's prospects. "If the law applies to all, then they will be successful. But if it is applied to some and others are left to roam the street, it will fail."

Part of the difficulty of the crackdown is that it involves taking to task the grassroots of Abbas's political party, who have joined the Al Aqsa cells while moonlighting as police officers. But with Abbas's political reputation staked on boosting personal security, and with the Israelis demanding an improvement as a prerequisite for progress on political talks, a confrontation may be approaching.

At least that is how the Al Aqsa militants in the old city see it."If they don't want us to carry weapons in the streets," says Saari Hussein, an Al Aqsa Martyrs Brigade member, "there will be a problem. If the PA tells me to put down my weapon, I won't listen. I'll shoot at whoever comes to arrest me."