PORT ST. LUCIE, Fla. — Mitt Romney on Monday will accuse the Obama administration of fundamentally misunderstanding the threat of radical Islam, using a major foreign-policy speech at the Virginia Military Institute to say President Obama is rejecting six decades of bipartisan consensus by not flexing more U.S. muscle on the world stage.
And after delaying for nearly a month, the Republican presidential nominee will sharpen his attack about the way Mr. Obama handled the assault on American diplomatic posts in Egypt and Libya.
According to excerpts, he will say the president’s first reaction was to blame an Internet video mocking Islam, and only belatedly to spot “the deliberate work of terrorists who use violence to impose their dark ideology on others.”
“Hope is not a strategy,” Mr. Romney will say. “We cannot support our friends and defeat our enemies in the Middle East when our words are not backed up by deeds, when our defense spending is being arbitrarily and deeply cut, when we have no trade agenda to speak of, and the perception of our strategy is not one of partnership, but of passivity.”
Mr. Romney will make the speech less than a week after resetting the race with a strong debate performance that has energized Republican voters and helped him capture the lead in polls in some of the key battleground states.
But Friday’s jobs report, which showed the unemployment rate dipped below 8 percent — to 7.8 percent, which is where it was when Mr. Obama took office in January 2009 — erased one of the Republican’s favorite talking points.
The economy has dominated the presidential race, but Iran’s nuclear program and the Sept. 11 attacks on the American Embassy in Cairo and the U.S. Consulate in Benghazi, Libya, have thrust foreign affairs into the headlines.
Mr. Obama and his advisers initially said the attacks were sparked by a video mocking the Prophet Muhammad, but have since acknowledged that the attack in Benghazi was orchestrated by terrorist elements linked to al Qaeda.
Mr. Romney will argue that Mr. Obama’s response to the attacks is emblematic of his overall approach to foreign affairs, which Mr. Romney said he will change by throwing around more American weight.
He said he will use foreign aid to pressure Egypt to protect democracy, will try to build the Syrian opposition and will try to restart negotiations toward a two-state solution for the Israelis and Palestinians.
“I believe that if America does not lead, others will — others who do not share our interests and our values — and the world will grow darker, for our friends and for us,” he will say. “America’s security and the cause of freedom cannot afford four more years like the last four years.”
The Obama campaign said Mr. Romney hasn’t shown that he is up to the task of handling foreign policy.
“We’re not going to be lectured by someone who has been an unmitigated disaster on foreign policy every time he’s dipped his toe in the foreign policy waters,” Obama campaign spokeswoman Jen Psaki told reporters traveling aboard Air Force One on Sunday.
She recounted Mr. Romney’s summer trip to Europe and Israel, where he had to make amends for saying London didn’t seem fully prepared for what turned out to be a successful Olympics.
“The only person who has offended Europe more is probably Chevy Chase,” Ms. Psaki said, referring to the actor’s comedic movie “National Lampoon’s European Vacation.”
She said Mr. Romney would not have gone after Osama bin Laden as steadfastly as Mr. Obama did, and that it’s not clear what Mr. Romney would do differently pertaining to Iran.
That question about specific differences has dogged Mr. Romney throughout the campaign as Democrats and even some Republicans have questioned how his tougher talk translates into specific policies.
The Republican’s advisers, though, said he starts from a completely different philosophy that begins with the belief that the fight against terrorism can’t be conducted surgically.
“While drones and drone attacks are worthwhile and it’s good to kill bad guys, you fundamentally misunderstand this struggle if you think that’s the answer to it,” said Richard S. Williamson, a former assistant secretary of state who is advising Mr. Romney.
Mr. Romney chose VMI, in Lexington, Va., to deliver the speech because it was the alma mater of George C. Marshall, who as secretary of state and secretary of defense helped craft the foreign policy that guided Republicans and Democrats after World War II.
Over the past week, the presidential race turned into a bit of a roller coaster, with Mr. Romney’s strong debate performance and then the release of unemployment numbers benefiting Mr. Obama.
Mr. Obama also announced his campaign and allied party organizations collected $181 million in donations in September.
The campaigns have spent several days wrestling over their contrasting economic messages. On Sunday, they exchanged rhetorical blows on the television talk-show circuit, and the battle spilled onto the television airwaves in Florida, which is a key state come Election Day.
The Obama camp is airing a television ad that accuses Mr. Romney of fudging the details of his tax plan, which the Republican says would cut rates by 20 percent across the board without deepening the deficit.
“Why won’t Romney level with us about his tax plan, which gives the wealthy huge new tax breaks?” a narrator says in the ad. “Because according to experts, he’d have to raise taxes on the middle class — or increase the deficit to pay for it.”
The Romney camp is countering with an ad that says Mr. Obama “is not telling the truth” about the Republican’s tax plan. The spot highlights a report by The Associated Press that says Mr. Obama’s claim “doesn’t add up” and the take of ABC News that the charge was “mostly fiction.”
“Obama’s plan? $4,000 more in taxes on the middle class,” the narrator says, pointing to a study from the American Enterprise Institute.
Mr. Romney went with that message at a campaign rally in Port St. Lucie, telling the more than 9,000 people in attendance that Mr. Obama has failed to fulfill his promise to reduce health care costs and that on his watch the nation has added more to the public debt than nearly all his predecessors combined.
“A study came out this week that showed with all this spending and all this borrowing and all the interest on that debt, that he will ultimately have to raise taxes on middle-income families by $4,000 per year,” he said before vowing, “I will not raise taxes on middle-income families.”
• Stephen Dinan reported from Washington.