For the first time since the war in Iraq began, more than half of the American public believes the fight there has not made the United States safer, according to a new Washington Post-ABC News poll.

While the focus in Washington has shifted from the Iraq conflict to Social Security and other domestic matters, the survey found that Americans continue to rank Iraq second only to the economy in importance -- and that many are losing patience with the enterprise.

Nearly three-quarters of Americans said the number of casualties in Iraq is unacceptable, while two-thirds said the U.S. military there is bogged down, and nearly six in 10 said the war was not worth fighting -- in all three cases matching or exceeding the highest levels of pessimism yet recorded. More than four in 10 said they believe the U.S. presence in Iraq is becoming analogous to the experience in Vietnam.

Perhaps most ominous for President Bush, 52 percent said the war in Iraq has not contributed to the long-term security of the United States, while 47 percent said it has. It was the first time a majority of Americans disagreed with the central notion Bush has offered to build support for war: that the fight there will make Americans safer from terrorists at home.

More than half -- 52 percent -- disapprove of how Bush is handling his job, the highest of his presidency. A larger majority -- 56 percent -- disapproved of Republicans in Congress, and an identical proportion disapproved of Democrats.

For the first time, a majority, 55 percent, also said that Bush has done more to divide the country than to unite it.

-- Dana Milbank