Addressing the 94th annual American Legion convention in Indianapolis, Romney said the Democratic president has allowed the United States' status as a world leader to "diminish" and his plan to cut defense spending would be "devastating."
"In dealings with other nations, he has given trust where it is not earned, insult where it is not deserved and apology where it is not due," the GOP presidential nominee said in remarks prepared for delivery at the convention.
"We used to nurture our alliances and stand up for our common values. But when it comes to friends and allies like Poland, the Czech Republic and Israel ... and with nations that oppose us like Iran and Cuba ... President Obama has moved in the opposite direction. Our foreign policy should take a page from the U.S. Marine Corps: No better friend, no worse enemy."
Romney lamented the trillion dollars in defense spending cuts that are on the horizon without further congressional action. He said such deep cuts would "severely shrink our force structure and impair our ability to meet and deter threats."
"The devastation will be felt here at home, where up to 1.5 million jobs could be lost," he said.
"A year ago, President Obama told your national convention that, 'We cannot, we must not, we will not, balance the budget on the backs of our veterans.' I thought I finally agreed with him on something -- but now, he is on the verge of breaking that promise."
Romney said he and his running mate, Rep. Paul Ryan of Wisconsin, would "make reductions in other areas and install pro-growth policies to make sure that our country remains safe and secure."
"There are plenty of places to cut in a federal budget that now totals well over $3 trillion a year, but defense is not one of them," he said.
Former U.S. Secretary of Veterans Affairs Anthony Principi issued a statement saying Romney "understands that for our nation's veterans the fight doesn't end when they come home."
"Our returning vets have an unemployment rate that is significantly higher than that of the average American," Principi said. "We need a president who understands how to get the economy in gear so that it creates good jobs for everyone who seeks one, including our vets. After all our veterans have done for us, they deserve the dignity of pursuing the American Dream."