LEXINGTON, Va. — Republican presidential candidate Mitt Romney called for a change of course in the Middle East and slammed his rival’s foreign policy strategy as weak in a speech at Virginia Military Institute on Monday.

“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,” Romney said. “America’s security and the cause of freedom cannot afford four more years like the last four years.”

The speech lambasted President Barack Obama’s response to the Arab Spring, and specifically his administration’s handling of the violent attack on the U.S. consulate in Benghazi, Libya, on Sept. 11, 2012, that killed Ambassador Christopher Stevens and three other Americans.

“I want to be very clear: The blame for the murder of our people in Libya, and the attacks on our embassies in so many other countries, lies solely with those who carried them out — no one else,” Romney said. “But it is our responsibility and the responsibility of our President to use America’s great power to shape history — not to lead from behind, leaving our destiny at the mercy of events. Unfortunately, that is exactly where we find ourselves in the Middle East under President Obama.”

Coming off a strong performance last week in a debate that centered on domestic policy, Romney is looking to boost his reputation in the field of international relations, the topic of an upcoming debate on Oct. 22.

In his address before about 500 VMI cadets and local supporters in Lexington, Va., the former Massachusetts governor made his case to voters that he would be a more effective and capable commander-in-chief than Obama.

“I know the President hopes for a safer, freer, and a more prosperous Middle East allied with the United States. I share this hope,” Romney said. “But hope is not a strategy. 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.”

America should help organize and arm rebels in Syria, make aid to Egypt conditional on the development of democratic institutions as well as peace with Israel, and advocate a two-state solution to the Israeli-Palestinian conflict, Romney said.

“I will support friends across the Middle East who share our values, but need help defending them and their sovereignty against our common enemies,” he said.

Romney also said he would roll back Obama’s “deep and arbitrary cuts to the nation’s military, tighten sanctions on Iran and restore the permanent presence of aircraft carrier task forces in both the Eastern Mediterranean and the Gulf.”

There is almost always a carrier task force in the 5th Fleet region of the Persian Gulf and there are often two — as there are today, according to the U.S. Navy website.

Romney said Obama “missed an historic opportunity” to provide leadership during his term, a time of great upheaval in the Middle East.

“The 21st century can and must be an American century. It began with terror, war and economic calamity,” Romney said. “It is our duty to steer it onto the path of freedom, peace and prosperity.”

Romney’s foreign policy advisors say the speech was designed to communicate his commitment to “peace through strength,” a phrase Republican Ronald Reagan famously used in his successful run against Democrat Jimmy Carter.

The Romney campaign repeatedly has sought to draw comparisons between Obama and Carter, whose popularity suffered badly during the Iranian hostage crisis in 1979-80, undermining his bid for a second term.

“The American people are going to be asked to make a decision, and in the area of a foreign policy and national security, there’s a pretty bold choice,” said one of Romney’s advisors, former Ambassador Rich Williamson. Williamson likened Romney’s foreign policy approach to “bipartisan” strategies of Reagan, Harry Truman, John F. Kennedy and Bill Clinton in his second term.

“That of course is in great contrast to President Obama, who believes we are in decline, who believes that many forces are in control, and that we should lead from behind,” Williams said.

The Obama campaign didn’t wait for the speech to be delivered before hitting back.

In a press briefing on Sunday, Obama spokeswoman Jen Psaki said the administration refuses “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.”

Psaki cited a series of so-called “gaffes” by Romney that grabbed headlines during a trip abroad this summer. During the eight-day tour in July, Romney angered Brits by publically questioning their county’s readiness for the Olympic Games, and elicited charges of racism from Palestinians when he said during a fundraiser in Jerusalem that “culture makes all the difference” in Israel’s economic success.

More recently, Romney earned rebukes from some prominent Spanish politicians for his comment during last week’s debate that 42 percent of the U.S. economy is spent on government under Obama, a rate comparable to Spain. “I don’t want to go down the path of Spain,” he said.

Psaki also knocked Romney for failing to mention the war in Afghanistan during his acceptance speech at the Republican National Convention.

Romney “didn’t bring up Afghanistan, he didn’t bring up the troops,” Psaki said. “He has been abundantly clear that he would not have gone after Osama bin Laden in Pakistan; has failed to lay out his exact differences on Iran, as much as he said he has an entirely different position from the President.”

Psaki said Romney will have “a very high bar he would have to jump over” to prove that he’s prepared to be Commander-in-Chief and tackle the country’s foreign policy challenges.