WASHINGTON – President Bush picked up yesterday where his running mate left off in his contentious debate Tuesday night with Senator Edwards. In a scathing speech in Pennsylvania, Mr. Bush portrayed the Democratic ticket as wavering in the war on terror, favoring tax increases, and sending mixed signals to allies and foes.

In his most pointed attack yet on Senator Kerry, the president blasted his Democrat challenger for adopting a “strategy of retreat” when it comes to Iraq and of advocating an economic program that Mr. Bush says would endanger America’s recovery.

“There will be good days and bad days in the war on terror … we will stay in the fight until the fight is won,” the president said as he defended his decision to go to war in Iraq.

“Senator Kerry assures us that he’s the one to win a war he calls a ‘mistake,’ an ‘error,’ and ‘a diversion,'” Mr. Bush said, to cheers from a GOP audience. “But you can’t win a war you don’t believe in fighting.”

Mr. Bush said his rival’s “endless back-and-forth on Iraq is part of a larger misunderstanding.”

“In the war on terror, Senator Kerry is proposing policies and doctrines that would weaken America and make the world more dangerous,” the president said.

“Our object in the war on terror is not to wait for the next attack and respond but to prevent attacks by taking the fight to the enemy,” he said.

On the economy, Mr. Bush said: “My opponent is a tax-and-spend liberal. I’m a compassionate conservative. My opponent wants to empower government. I want to use government to empower people.”

In the absence from the campaign trail of Mr. Kerry, who was prepping for tomorrow’s debate with the president, Mr. Bush’s blistering attack drew a fierce response from Mr. Edwards. The North Carolina senator accused the president of being “completely out of touch with reality” about post-Saddam-Hussein Iraq and about the economy.

Noting that Bush advisers had touted their boss’s speech as a major address, Mr. Edwards said the president’s critique amounted to more of the same.

“The problem is, of course, when you got the same old tired ideas, the same old false attacks, the same old tired rhetoric, there are no new ideas. There are no new plans,” the vice presidential nominee told a cheering Democratic audience at the Palm Beach County convention center in Florida.

“They’re in denial. They’re in denial about everything,” he said.

Mr. Edwards repeated a line he used in his debate with Vice President Cheney and accused the administration of diverting attention from the real war on terror to go after Mr. Hussein instead.

“These are the men who think their experience and value is so important for the American people,” Mr. Edwards said.

The president’s delivery and focus yesterday were much sharper than in his performance in last week’s first face-to-face debate with Mr. Kerry, during which he scowled and grimaced as his opponent criticized him. Yesterday, the president offered an explanation for the frowns, saying that when you hear such criticism, “You can understand why somebody would make a face.”

Opinion polls have shown a tightening race since last week’s presidential debate in Miami, and GOP strategists hope that yesterday’s Bush speech, along with Mr. Cheney’s performance in Tuesday’s debate, will stop the Democratic ticket from gaining any more ground and give the Republican ticket more impetus going into tomorrow’s Bush-Kerry debate.

Bush campaign strategists say Mr. Cheney did exactly what they were looking for him to do in the encounter with Mr. Edwards. They say he made an effective case for the war in Iraq and kept the heat on the Democrats by exploring their Senate records and exposing their pattern, as the vice president put it, “of always being on the wrong side of defense issues.” Campaign officials say Mr. Cheney’s assertiveness excited a GOP base that was disappointed with the president’s debate with Mr. Kerry.

Kerry campaign advisers disagree about who had the edge in the toughly adversarial encounter between Mr. Cheney and Mr.Edwards. “I thought it was another win for the Kerry-Edwards team. I thought John Edwards showed real strength, conviction, he was in command of all the facts, in control of the debate,” the Democratic Party chairman, Terry McAuliffe, said. “I think the burden was on Dick Cheney to try and knock it out of the park. He did not do that.”

The Democratic National Committee launched a post-vice-presidential debate “reality check” video yesterday on its Web site, showing video clips of Mr. Cheney seeming to contradict statements he made during the debate.

“Someone who lies about the little things will lie about the big things, too,” Mr. McAuliffe told reporters in a conference call.

Both running mates managed to land some telling blows in what was seen as a more even contest than Mr. Kerry’s first debate with Mr. Bush. Polls were split on who came off better from the barbed confrontation between running mates. Mr. Cheney fared best in an ABC News poll of registered voters, with 43% giving the vice president the edge while 35% gave the nod to the Democrat. But a CBS News phone poll of 178 undecided voters found that 41% thought Mr. Edwards had won, compared to 28% who thought Mr. Cheney had.

Bush advisers say Mr. Cheney’s performance has buoyed the president, who is likely to be far more assertive tomorrow night in St. Louis in his second face-off with Mr. Kerry. The former Massachusetts governor William Weld, who has been advising the Bush campaign on debate strategies, argues that the president must pay more attention to what Mr. Kerry says and respond to the senator’s remarks, rather than concentrating on delivering prepared lines. Mr. Weld held a marathon series of eight debates with Mr. Kerry in the Massachusetts Senate campaign of 1996.