A new public-opinion poll shows President Bush is losing support for his handling of the fight against terrorism and the decision to invade Iraq.

For the first time, more than half of those surveyed in the monthly Washington Post/ABC News poll say the war in Iraq was not worth fighting.

The poll shows 70 percent of Americans believe U.S. casualties in Iraq have reached an unacceptable level. That is up six points from April.

In that time, Mr. Bush has also seen a 13 percent drop in public approval for his handling of the fight against terrorism, putting him about even on that issue with his presumptive Democratic challenger, Massachusetts Senator John Kerry.

Asked about the new survey, White House Spokesman Scott McClellan says the president is not going to get caught up in poll numbers as he continues to focus on his plan for success in Iraq.

Mr. McClellan says that plan is making tremendous progress, and Mr. Bush will continue to talk to the American people about that progress to help the Iraqi people realize a free, democratic, and peaceful future.

The White House spokesman says Americans recognize that what the United States is working to achieve in Iraq will help make the world a better and safer place, and make America more secure.

The new poll shows Americans are sharply divided over whether the war has made them safer, with 51 percent saying it has. That is a new low for the poll that also shows a majority believing the war has not improved prospects for long-term peace and stability in the Middle East.

Mr. McClellan says terrorists in Iraq are seeking to derail the transition to democracy. Challenges remain and there will be more difficulties along the way, he says, but the president will stick to his message that what Washington is working toward will make America more secure by helping to transform a dangerous region of the world.

Mr. McClellan says the Bush Administration has always said it expects this year's presidential election to be extremely close, so public-opinion polls must be looked at together.

Asked who they plan to support in the November election, the new Washington Post/ABC News poll shows Senator Kerry leading President Bush by four points. Mr. Kerry scored higher on honesty, trustworthiness, and understanding people's problems.

President Bush scored higher than Senator Kerry on making the country safer and being a strong leader. The president's numbers on the economy are also up seven points since March in his strongest showing since January with 46 percent of those polled giving him positive marks on the economy.

The president's overall job approval rating held steady at 47 percent with his disapproval rating reaching a new high of 51 percent.