WASHINGTON, Oct. 19 — President Bush’s chief spokesman conceded today that the latest carnage in Iraq was somewhat reminiscent of the 1968 Tet offensive in Vietnam, which helped to turn public opinion against the war in Southeast Asia. But he said the president still envisioned victory in Iraq.

The surge in violence in Iraq is a reminder “that terrorists try to exploit pictures and try to use the media as conduits for influencing public opinion in the United States,” Tony Snow, the White House spokesman, said as Mr. Bush prepared to campaign for Republicans today in Pennsylvania and Virginia.

Mr. Snow fielded questions at a particularly delicate time: just after a senior American officer in Iraq said that the current approach to stemming the chaos in Baghdad was not working, and as the approaching Congressional elections are stoking fears of a Republican disaster because of the war.

Mr. Snow recalled that while the Tet offensive may have been the tipping point as far as American public opinion was concerned, it was later found to have been extremely costly for the Communists — arguably a “victory” for the United States military. But the American public was so tired of the war by that time that President Lyndon B. Johnson was driven into retirement, and Richard Nixon was elected in part on a pledge to end the conflict.

Asked if he saw a similar portent in Iraq, Mr. Snow replied: “No. The important thing to remember is the president’s determined to win.” The administration will “make adjustments as necessary,” Mr. Snow said, “but the one thing that nobody should have any doubt about is that we’re going to win.”

President Bush himself acknowledged the possible parallel between the Tet offensive and the bloodletting in Iraq, as suggested by Thomas L. Friedman in a column in The New York Times.

“He could be right,” Mr. Bush said on Wednesday in an interview with George Stephanopoulos of ABC. “There’s certainly a stepped-up level of violence, and we’re heading into an election.” Mr. Bush went on to say, “They believe that if they can create enough chaos, the American people will grow sick and tired of the Iraqi effort.”

The White House has long resisted suggestions that, in embarking on a war in Iraq, the United States may be sliding into a Vietnam-like “quagmire.” Mr. Bush and his commanders have vowed to adjust tactics as needed in the drive to establish an Iraq that is free, stable and able to defend itself.

Maj. Gen. William B. Caldwell IV, the senior military spokesman in Iraq, said today that the approach of concentrating on a limited number of troubled enclaves in Baghdad was not working as well as expected, and that the upsurge in violence in the Baghdad area was “disheartening.”

Mr. Snow, the White House spokesman, emphasized that he accepted the parallel with the Tet offensive only in a “very limited” context: an attempt by an enemy to influence American public opinion just before an election.

“We do not think that there’s been a flip-over point,” he said. “But more importantly, from the standpoint of the government and the standpoint of this administration, we are going to continue pursuing victory aggressively.” To do otherwise, the White House has said repeatedly, would be to allow Iraq to become a spawning ground for terrorists.

President Bush says he sees a possible parallel in the increase in violence in Iraq and the 1968 Tet offensive that prompted Americans to lose support for the Vietnam War.

But the White House on Thursday said the president had not been making the analogy that Iraq had reached a similar turning point. Instead, he was saying that insurgents were possibly increasing violence to try to influence coming U.S. elections.

Bush was asked in an ABC News interview on Wednesday whether he agreed with an opinion by New York Times columnist Thomas Friedman that the current violence in Iraq was "the jihadist equivalent of the Tet offensive."

Bush responded: "He could be right. There's certainly a stepped-up level of violence, and we're heading into an election."

Bush and other top U.S. officials have long resisted comparisons to the Vietnam War when critics have suggested that Iraq has turned into a quagmire.

They also have stepped back from adamant declarations of progress as sectarian violence ratchets up, with more than 2,750 American troops and tens of thousands of Iraqis killed since the U.S.-led invasion in March 2003.

Bush has taken a more flexible tone on Iraq, saying he is open to adjusting policy, as the November 7 elections approach with his Republican Party facing the possibility of losing control of the U.S. Congress over an unpopular war.

Communist forces lost the Tet offensive, but it was a major propaganda victory and is widely considered a turning point of the war in Vietnam, prompting support for the conflict to deteriorate. President Lyndon Johnson's popularity fell and he withdrew as a candidate for re-election in March 1968.

White House spokesman Tony Snow said the president was not trying to say that it was the turning point in Iraq, as the Tet offensive has come to symbolize for Vietnam.

"That is not an analogy we're trying to make," Snow said. "We do not think that there's been a flip-over point, but more importantly from the standpoint of the government and the standpoint of this administration, we're going to continue pursuing victory aggressively."

Bush has maintained that Iraq is not embroiled in civil war and continues to insist that U.S. troops will not leave until Iraqis can take over security for their country.

Bush told ABC that not every American soldier would be out of Iraq before he leaves office in about two years. There are about 144,000 U.S. troops currently in Iraq.

"Look, here's how I view it," Bush said. "First of all, al Qaeda is still very active in Iraq. They are dangerous. They are lethal. They are trying to not only kill American troops, but they're trying to foment sectarian violence.

"They believe that if they can create enough chaos, the American people will grow sick and tired of the Iraqi effort and will cause government to withdraw," he said.

(Additional reporting by Steve Holland)