Baghdad ? Iraq delayed until today a crucial vote in parliament on a pact that would keep U.S. troops in Iraq through 2011 after lawmakers, many of them Sunni Arabs, demanded concessions from the Shiite-led government in return for supporting the deal.

The one-day delay and Wednesday’s backroom haggling highlighted Iraq’s deep divisions, as well as the fluid and often chaotic nature of its politics nearly six years after the U.S.-led invasion that ousted Saddam Hussein.

In the past, sectarian-based disputes and other quarrels among Iraqi politicians have stalled efforts to achieve national reconciliation, although some key compromises have been achieved. While the country appears to be emerging from years of intense violence, mistrust among key factions that seek to preserve or advance their own interests has slowed political progress.

The proposed security agreement provides for the first time since the 2003 invasion a timeline for the withdrawal of U.S. troops and offers what Prime Minister Nouri al-Maliki describes as a path toward full sovereignty for Iraq.