The leader of Turkey's ruling party was expected to win a by-election Sunday, moving him a step closer to becoming the next prime minister as the country wrestles with whether to accept 60,000 U.S. troops for a possible Iraq  war. Recep Tayyip Erdogan has been the main power behind the scenes since his Islamic-rooted party formed a government after November elections, but he was barred from political office until a recent constitutional change.

Erdogan is running for a seat in parliament in the southeastern province of Siirt. If he wins, he is expected to replace Prime Minister Abdullah Gul and form a new Cabinet within days - possibly removing ministers who have opposed the U.S. deployment.

Polls opened at 6 a.m. and results were expected by the end of the day.

Washington is pressing its longtime ally to quickly authorize the troop deployment to open a northern front against neighboring Iraq.

Last week, Turkey's parliament rejected a resolution that would have allowed the American force, and the government is evaluating whether to resubmit it for a second vote.

Most analysts said a new resolution is unlikely before Erdogan forms a new government.

Several Cabinet ministers have spoken out against the deployment and would likely refuse to give their necessary approval to a second resolution. The daily Hurriyet reported Saturday that when Erdogan reshuffles the Cabinet, he plans to reduce the number of ministers from 24 to 20 and leave out ministers opposed to the U.S. deployment.

Erdogan and Turkey's government have argued that Turkey risks straining ties with the United States and losing a say in the future of Iraq if it does not let in the U.S. troops.

Beyond that, 15 billion dlrs is at stake. The United States promised the money as aid to Turkey to offset predicted economic loses from a war. But the money is contingent on deploying U.S. troops.

There are few doubts that Erdogan will win one of the three seats on the ballot in Siirt, 60 miles north of the Turkish-Iraqi border. Erdogan said Saturday that his party would likely win all three seats.

In November elections, the Justice party came in second to the pro-Kurdish Democratic People's Party in the city of Kurds, Turks and Arabs. The pro-Kurdish party cannot run in Sunday's by-elections because it did not pass the 10 percent cut off in November.

Erdogan and Gul have shared the spotlight ever since the Justice and Development party's victory in November. Although Gul is head of the government, he rarely takes any decisions without consulting Erdogan.

Erdogan, 49, was also the one invited for talks by foreign leaders, including President Bush .

According to the constitution, Turkey's prime minister must be a member of the 550-seat parliament. Erdogan was barred from running in the November elections because of a conviction for inciting religious hatred over a poem he read at a rally in Siirt.

The party's lawmakers voted to change the constitution to allow Erdogan to run for office.

The by-elections were scheduled after Turkey's election board found evidence that a ballot box in Siirt had been tampered with.


PHOTO CAPTION

Recep Tayyip Erdogan, Turkey's governing party leader, left, stands with Prime Minister Abdullah Gul in this March 4, 2003 file photo. Erogan said Saturday he was optimistic that his party would sweep by-elections that pave the way for him to become prime minister. Erdogan, who is running in Sunday's poll in the southeastern province of Siirt, is expected to replace Prime Minister Abdullah Gul and form a new Cabinet within days, ending months of confusion over Turkey's leadership. (AP Photo/Burhan Ozbilici/Fil