They fought Saddam Hussein and they have fought each other. But Jalal Talabani, the President of Iraq, and Masoud Barzani, President of the Kurdistan Regional Government, never imagined anyone would fight them for political control of Iraq's Kurds.

Mr. Talabani's Patriotic Union of Kurdistan and Mr. Barzani's Kurdistan Democratic Party have formed an alliance to contest Sunday's national elections. But their hold on the Kurdish provinces is being challenged by an upstart party that threatens to alter the balance of political power in Iraq.

That threat, some believe, cost the life of a man in a small community on the road to Halabja, the Kurdish town known to the world as the place where Mr. Hussein used chemical weapons to slaughter 5,000 of his own people in 1988. It was in this town, known as New Halabja, with a view of the snow-covered mountains that border Iran, that Rauf Zarayani, a 54-year-old regional organizer for a new Kurdish political party called Goran (Change), was gunned down outside his home one unseasonably warm afternoon in January.

"He was killed for political purposes," said Garmian, 31, the oldest of Mr. Zarayani's 17 children. "He had no other enemies."

In a few short months, the party that made its debut in Kurdistan's regional elections last July has transformed Kurdish politics. Led by two men who until a year ago were part of the inner circle of Mr. Talabani's PUK, Goran stunned people when it captured 25 of the 100 seats at stake in that election, mostly at the expense of the PUK.

The young party has gone on to build widespread support in the current national election campaign. Even PUK spokesman Abdulrazzaq Abdullah concedes that Goran will win at least as many seats as the PUK in Sulaymaniyah, the home province of Mr. Talabani. Mr. Abdullah expects Goran will win as many as 12 of 60 seats across the Kurdish north of Iraq in Sunday's parliamentary vote. Mohamad Tofiq, Goran's second-in-command, puts the number closer to 20. That would add up to a revolution in Kurdish politics.

For one thing, it would likely mean the end of Mr. Talabani's presidency. While the PUK and KDP have a 10-year unity agreement, the rise of Goran at the expense of the PUK can't help but diminish Mr. Talabani's political lustre.

For another, it may finally lead to the resolution of an issue that lies at the heart of Kurdish politics: the retrieval of the city of Kirkuk and its surrounding region. Kurds, Arabs and Turkmen lay claim to the oil-rich area straddling the Kurdish north and Arab south.

Mr. Tofiq is critical of the Kurdish leadership not only for failing to resolve the issue of Kirkuk and other disputed territories, but for not even having a plan for how to do so. Goran, he said, will push to allow Kirkuk's representatives in the Iraqi parliament, including perhaps three Goran members among the region's seven seats, to settle the issue. "They're the representatives of the people of Kirkuk," he said. "They should decide."

And what if they decide that Kirkuk need not be made part of the autonomous region of Kurdistan? "So be it," Mr. Tofiq said. "Our job is to persuade the people of the south that it is in their interest to let Kirkuk go."

Though a regional party in a national election, Goran is campaigning on the principle that all politics is local. That is why it is willing to put the future of Kirkuk in the hands of the city's MPs and concentrate instead on ending the corruption that undermines the quality of life of Iraqis.

"People see all the fancy new buildings here, the five-star hotel, like some kind of mini-Dubai," Mr. Tofiq said. "And they see the overcrowded public schools with four shifts of students. Where are the priorities? The people aren't going to take this any more."

According to Mr. Tofiq, he and Goran's leader, Nawshirwan Mustafa, tried to encourage reform from within the PUK. Both were senior members of the party (Mr. Mustafa was second-in-command to Mr. Talabani) and both were veteran peshmerga who had spent years in the mountains hiding from Saddam Hussein and launching guerrilla raids on his forces. But their ideas for greater transparency in budgets and decision-making were spurned.

"The old party is living in the past, still wanting to reward its fighters," Mr. Tofiq said. "It's time to move on."

Mr. Abdullah, the PUK spokesman, challenges the accusations of corruption as "political rhetoric." But a PUK member of parliament acknowledges it exists. "You have to understand," he said, "this place was at war, and after every war it's natural for the winning side to start from scratch and put its own people in charge and to help its friends."

Mahmoud Othman, an independent Kurdish MP, says he has enormous respect for Goran's leaders. "They've taken on a big challenge and are really shaking things up," he said. "For the PUK especially, they're a big threat."

Is it possible that Rauf Zarayani's killing was, indeed, a political assassination?

"Maybe yes, maybe no," said Mr. Abdullah. "That's for the police and judiciary to determine.

"I can say," he added, "that we're very sad this happened. After all, we're in charge of security in that area."

The attack came amidst a number of apparent efforts to intimidate Goran organizers. Some report they received threatening phone calls, others that they were assaulted by goons wielding steel bars.

Last week, observers say, several PUK vehicles drove through the middle of a Goran street rally. Three people were hurt.

In New Halabja, the younger Mr. Zarayani, his Kalashnikov at his side, said the 24 members of his family remain committed to reform and an end to the rule of Mr. Talabani and Mr. Barzani.

"It doesn't matter if they use chemical weapons against us," he said, recalling the region's bitter past. "We will still support Goran and we'll still fight to remove these people."