BAGHDAD — Barack Obama's victory is already beginning to shift the political ground in Iraq and the region.

Iraqi Shiite politicians are indicating that they will move faster toward a new security agreement about U.S. troops, and a Bush administration official said he believed that Iraqis could ratify the agreement as early as the middle of this month.

Obama has said that he favors a 16-month schedule for withdrawing combat brigades, a timetable about twice as fast as that provided for in the draft U.S. and Iraqi accord.

Many Shiite politicians had been under intense pressure from Iranian leaders not to sign a security agreement. Iran, which has close ties to Shiite politicians, has feared the agreement would lay the groundwork for a permanent U.S. troop presence in Iraq that would threaten Iran.

Now the Iraqis appear to be feeling less pressure from Iran, perhaps because the Iranians are less worried that an Obama government will try to force a regime change in their country.

Of course, given the volatile and fractious state of Iraqi politics, the security agreement could still be delayed. But with Iraqis believing that Obama, as president, would move faster to withdraw U.S. troops, Iraqi and U.S. officials said obstacles to a security agreement appeared to be fading.

Jabeer Habib, an independent Shiite lawmaker and a political scientist at Baghdad University, put it simply: "Obama's election shifts Iraq into a new position."

Obama's election also coincided with the U.S. negotiators' acceptance of many of the changes Iraqis demanded in the agreement, which created an overall picture that was easier both for the Iraqis and their neighbors — Iran, Syria and Saudi Arabia — to accept.

The U.S. negotiators sent a new version of the agreement to Iraqi leaders on Thursday that included many of the changes Iraqis had demanded. In public, Iraqis said merely that they were studying the document.

The Americans also added language to make explicit what kinds of troops would remain after the withdrawal in 2011, said a Bush administration official knowledgeable about the security pact. Those still in Iraq would be primarily trainers and air-traffic controllers, the official said.

"There's going to be a significant presence, but they are not going to be 'combat' forces," said the administration official. The official said that the most recent talks with Iraqis had given U.S. negotiators confidence that a final agreement was close.