"The only thing respected by thugs and tyrants is our resolve, backed by our power and our readiness to use it," the former Massachusetts governor said in a speech via satellite from Columbus, Ohio, to the American Israel Public Affairs Committee.
Like his GOP rival Rick Santorum, Romney took issue with Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, who said recently on CNN that he believes some Iranian officials are "rational actors."
"There are some in this administration who argue that Iran's leaders are `rational,' and that we can do business with them," Romney said. "The president speaks of common interests. Let me be clear: we do not have common interests with a terrorist regime."
Romney's attacks on Obama have in turn drawn criticism from Democrats. Senate Foreign Relations Committee Chairman John Kerry, D-Mass., told The New York Times that Romney's earlier accusation that Iran would get a nuclear weapon while Obama is president but would not if he is in the Oval Office "is the most craven political thing to say." Kerry also said overly hawkish talk could drive up oil prices.
But the Romney campaign remains convinced it can score points with pro-Israel voters by playing up its perceived differences on the issue, even as some experts say those differences actually are minimal. The Romney campaign put out a memo from policy director Lanhee Chen rebuking what it called the top six exaggerations of Obama's Sunday address to AIPAC.
Romney also said the Obama administration "has distanced itself from Israel and visibly warmed to the Palestinian cause," despite Palestinians' professed disappointment with his pro-Israel remarks to AIPAC and his urging of the United Nations last year not to recognize Palestinian statehood.
"It has emboldened the Palestinians," Romney said. "They are convinced that they can do better at the UN - and better with America - than they can at the bargaining table with Israel."
With so much turmoil in the Arab world, he said trying to negotiate any sort of peace process with the Palestinians would be like "setting up a tent in the middle of a hurricane," and that his support was unequivocally behind the Israelis.
Though he said Israeli and U.S. officials may disagree behind closed doors, he reiterated that he would never publicly admonish the Jewish state: "Israel does not need public lectures about how to weigh decisions of war and peace. It needs our support."
Romney also invoked his friendship with Israel's Prime Minister Benjamin Netanyahu, whom he called an "old friend" from having worked together three decades ago at the Boston Consulting Group.(Watch video: Romney and Santorum use the same phrase at AIPAC)