“The public sees what’s happening in Iraq, they see the persistent violence, and they want to make sure that we’re adapting,” Mr. Bartlett said.

He said the White House and the Republican Party were not about to cede the traditional advantages on national security to Democrats. Mr. Bush, he added, would step up his attacks on their national security credentials at campaign appearances in Pennsylvania and Virginia on behalf of two of the most endangered candidates, Senator George Allen of Virginia and Representative Don Sherwood of Pennsylvania.

Mr. Bartlett said Iraq remained a winning issue in the broader context of the war on terrorism, which the party would continue to hit hard.

Mr. Bush tried to do that on Wednesday in an interview on ABC News, telling George Stephanopoulos, the interviewer, that when voters go to the polls on Nov. 7 “they’re going to want to know what that person’s going to do, what is the plan for a candidate on Iraq, what do they believe?”

When Mr. Stephanopoulos asked Mr. Bush whether the increasing violence in Iraq was similar to the Tet Offensive in 1968, the Vietnam War campaign that is often cited as turning American opinion against the war, Mr. Bush said such a comparison “could be right,” suggesting that terrorists were aiming for a similar result.

Mr. Bush’s aides said he would continue to criticize Democrats on the war even if his words were not echoed by Republican candidates the way they were in 2002 and 2004.

In this environment, several Republicans said they had given up on trying to win an advantage on the war and would be satisfied in at least wrestling Democrats to a draw on it.