Washington ? An overwhelming majority of the public believes fighting between Sunni and Shiite Muslims in Iraq will lead to civil war, and half say the United States should begin withdrawing its forces from that violence-torn country, according to the latest Washington Post-ABC News poll.

The survey found that 80 percent believe that recent sectarian violence makes civil war in Iraq likely, and more than a third say such a conflict is “very likely” to occur. These expectations extend beyond party lines: More than seven in 10 Republicans and eight in 10 Democrats and political independents say they believe such a conflict is coming.

In the face of continuing violence, half – 52 percent – of those surveyed said the United States should begin withdrawing forces. One in six favor immediate withdrawal of all troops, while about one-third prefer a more gradual return.

The survey shows support for the war in Iraq has dissolved since the first months after the U.S. invasion. At the end of 2003, 59 percent said the conflict was worth the cost; today, 42 percent share that view.

The president’s overall job approval rating stood at 41 percent, essentially unchanged from January. Nearly six in 10 disapproved of his job performance, the 11th consecutive survey since last April in which at least half the country was critical of Bush’s leadership.

A total of 1,000 randomly selected Americans were interviewed March 2 to 5. The margin of sampling error for the overall results is plus or minus 3 percentage points.