SARAI SUBHAN AGHA, Iraq, Feb. 23 - The camouflage-clad militiamen marched down from the mountains in four columns of hundreds each, stomping their boots in unison.
"Keep looking forward!" an officer yelled.
"Kurdistan or death!" the soldiers shouted at once, their words thundering over the sound of heels striking the ground.
Here at a training camp in the eastern hills of Iraqi Kurdistan, there is little doubt about to whom these soldiers owe their allegiance.
Many say their first loyalty lies with a major Kurdish political party. Then they offer it to Kurdistan, the rugged autonomous region in northern Iraq the size of Switzerland. There is little mention of the nation of Iraq or the Iraqi Army.
"All of the pesh merga of Kurdistan, we're fighting for Kurdistan," one of the soldiers, Fermen Ibrahim, 25, told a visitor, calling the militia by its Kurdish name, which means "those who face death."
As political jockeying rages in Baghdad to determine the shape of the new government - how Islamic it will be, whether it has strong or weak central powers - one of the most troublesome issues emerging is whether political parties, especially those of the Kurds and Shiites, can keep their private armies. Kurdish leaders say they intend to write into the new constitution a system granting considerable powers to individual regions, one that will legitimize their use of the pesh merga.
If the Kurds succeed, they will achieve the right of regional powers to set up their own armies, possibly leading to warlord-style fiefs across Iraq. Until their strong showing in the recent national elections, Kurdish leaders appeared to agree, at least in public, with the American goal of dismantling militias. Now they stand in open defiance of it.
The pesh merga, with recruits from two Kurdish parties, total about 100,000 soldiers. A source of ethnic pride, they fought tenaciously against Saddam Hussein and are now relied upon by American commanders to battle the Arab-led insurgency in the north. Perhaps most important in the current power vacuum, they provide Kurdish leaders with armed backing in their demands for broad autonomy.
"We want to keep our pesh merga because they are a symbol of resistance," said Massoud Barzani, the leader of the Kurdistan Democratic Party and the son of Mustafa Barzani, a revered Kurdish leader who founded the pesh merga in the 1960's. "It's not a matter to be discussed or negotiated."
If the Kurds get the constitution they want, the pesh merga would nominally fall under the oversight of the Ministry of Defense in Baghdad, Kurdish officials say, but in reality would be controlled by regional commanders. The two Kurdish parties each have a ministry of pesh merga, which they say they intend to keep.
The Kurds also say the pesh merga will maintain all the trappings of a conventional army, with an officers' college, training camps and armor and artillery units all operating independently of the rest of the Iraqi security forces.
The major Shiite parties, who have the largest share of seats in the constitutional assembly, may try to block the Kurds on the militia issue to limit the autonomy of the Kurds. But those parties have significant militias that they may seek to keep, or to at least incorporate into the Iraqi security forces as intact units. Their armies generally stay hidden on the streets of Baghdad but have been active in the Shiite heartland of the south, operating checkpoints and patrols and, in some cases, enforcing strict Islamic law, like cracking down on alcohol vendors.
The leaders of the Supreme Council for the Islamic Revolution in Iraq, a powerful Shiite party, have repeatedly said that the party's Iranian-trained armed wing, the Badr Organization, at least 15,000 strong, can help provide security in the new Iraq.
The former governing Sunni Arabs, a minority now feeling threatened by the other groups, will probably oppose any move by the Kurds and Shiites to legitimize their militias.
American commanders publicly say that all armed groups in Iraq must be state sponsored and that militarized units should not be organized by ethnicity or sect. But they privately acknowledge the extreme difficulties of breaking up the militias. Lt. Col. Eric Durr, the head of civil affairs for the 42nd Infantry Division, charged with overseeing eastern Kurdistan, said it was now up to the new Iraqi government to figure out what to do with the militias.
"It's really a political issue for the Iraqi government to work out," he said.
The Americans are relying on the pesh merga to fight insurgents. Across the north, particularly in the besieged city of Mosul, American commanders have supported Iraqi officials in deploying large units of armed Kurds into the streets.
But the pesh merga also exemplify the pitfalls of private armies - in the mid-1990's, the militias of the two Kurdish parties turned their guns on each other in a civil war that left at least 3,000 dead.
"What I see happening now in Iraq is the potential drift toward warlordism," said Larry Diamond, a former adviser to the Coalition Provisional Authority, which tried but failed to disband militias before handing sovereignty to the Iraqis last June.
"If things go bad," he added, "if the center does not hold, if ethnic and regional divisions are not well and carefully managed by the country's political leaders, particularly at the center, then the existence of all these militias - both those preceding the handover of power and those that have arisen in recent months - could facilitate the descent of the country into some kind of Lebanon-style civil war."
The presence of the pesh merga "is bound to strengthen the resolve of Kurdish political leaders not to yield on their demands for far-reaching autonomy," said Mr. Diamond, a senior fellow at the Hoover Institution at Stanford University.
The pesh merga are everywhere in Iraqi Kurdistan - along the highways, atop government buildings, riding in convoys. They wear a hodgepodge of uniforms, from traditional baggy outfits to desert camouflage hand-me-downs from the United States Army. There is one thing that appears to be consistent, though: they think of themselves as Kurds first and Iraqis second.
"If I work hard to protect my people and my cities, indirectly I'll serve Iraq," Col. Mehdi Dosky, 44, the commander of the training camp here, said as he sat behind his desk in a dark green Iraqi Army uniform. Two officers on a couch pored over evaluation forms of the trainees. A map on one wall showed the theoretical pan-Kurdish nation that Kurds in the Middle East hope to carve out one day - a huge territory stretching from the Mediterranean to western Iran and taking in large parts of Turkey, Syria, Iraq and Iran.
"We don't think it's a good idea to disband our army," said Colonel Dosky, whose father served as a pesh merga from the militia's first days. "We want to keep our forces and have them protect our region. The Kurds will protect their area, and other people will use their forces to protect their own areas. There are too many ethnic and religious problems right now in Iraq."
The American dependence on such proxy armies is clearest in Mosul, where Kurds make up nearly a quarter of the population. In November, Sunni Arab rebels overran police stations and forced thousands of officers to quit, and the Arab governor requested the aid of two Kurdish battalions of the Iraqi National Guard.
Brig. Gen. Carter Ham, the head of Task Force Olympia, the American force which until last week was charged with controlling Mosul, used Kurds to guard his headquarters.
But the presence of an ethnic or sect-based militia in a diverse city can quickly inflame tensions.
Such is the case in Kirkuk, the oil-rich city where Kurds, Arabs and Turkmen uneasily live side by side. At the request of Arabs and Turkmen, the American military asked pesh merga to leave the city after Mr. Hussein fell. Last summer, Kurdish officials said, the Americans allowed 300 pesh merga to return temporarily to fight insurgents.
"Always, it's a sensitive issue," said Suphi Sabir, a senior official in the Iraqi Turkmen Front, the most prominent Turkmen party in Kirkuk. "But we won't start a fight over it because the result would be very bad."
Warzer Jaff contributed reporting from Mosul, Iraq, for this article.