Mitt Romney made a point of insisting that he would adhere to an unwritten rule and often violated rule about candidates not criticizing each other or contradicting American foreign policy on foreign soil. About the only effort he made to keep that promise during his stop in Israel was to avoid mentioning President Obama by name.

Beyond that, with some of the biggest investors in Republican politics in tow, Mr. Romney made no effort to disguise the target and intent of rhetoric that was certainly inflammatory but largely free of any sense of how we would carry out policies he was championing.

The message — on Iran, Jerusalem, the Palestinians — was all anti-Obama: Mr. Romney would be a much better friend to Israel than Mr. Obama ever could be. He would be much tougher on Iran. He would recognize Jerusalem as the capital. For good measure, he insulted the Palestinians by declaring that cultural differences — not decades under Israeli occupation — are the reason Israelis are more successful economically. It’s hard to say how this could affect policy if he were president, but it is not encouraging.

The real audience for Mr. Romney’s tough talk was American Jews and evangelical Christians, some of whom accompanied him on his trip. He is courting votes and making an aggressive pitch to donors, including Sheldon Adelson, the billionaire casino magnate with the hard-line pro-Israel views who is spending more money than any other American — $100 million — to defeat Mr. Obama.

Despite what Mr. Romney says, all American presidents have been pro-Israel, including Mr. Obama. But that doesn’t mean subcontracting American policy to Israeli leaders or donors. Mr. Romney hit an applause line by calling Jerusalem Israel’s capital and agreeing to consider moving the United States Embassy there from Tel Aviv. But those policies would complicate America’s ability to act as a broker in Israeli-Palestinian peace efforts.

Mr. Romney did American interests no favors when he praised Israeli economic growth while ignoring the challenges Palestinians face living under Israeli rule in the West Bank and Gaza. He showed troubling ignorance by understating the income disparity between Israel and those areas. Israel, in 2009, had a per capita gross domestic product of roughly $29,800, while, in 2008, the West Bank and Gaza had a per capita gross domestic product of $2,900, according to the Central Intelligence Agency.

On Iran’s nuclear weapons program, both Mr. Obama and Mr. Romney support trying to halt it with sanctions and negotiations but say military action is an option. It is unclear if Mr. Romney, as president, might structure sanctions differently and how committed he is to negotiations.

Already, one of his advisers is contending that Mr. Obama’s strategies have “failed.” On Sunday, Prime Minister Benjamin Netanyahu of Israel seemed to agree. Meanwhile, Mr. Romney ruled out any outcome that would contain rather than eliminate Iran’s nuclear program, and he strongly defended Israel’s right to strike Iran in self-defense. Mr. Obama also recognizes this right, but he has urged Israel to hold back, at least while negotiations are under way.

The tough talk raises concerns that Mr. Romney and his hard-line advisers may be more eager to take military action. Iran’s nuclear ambitions are a threat to Israel, the United States, its Arab neighbors and its own people. But there should be no illusions about the steep costs and limited returns of any attack on Iran’s nuclear complex.

Presidents often say things on the campaign trail that they don’t mean or regret and reverse once in office, but voters can only judge a candidate on his words. The more Mr. Romney digs in on a particular position, the harder it will be to dig out, especially if the people egging you on in the first place have just donated $100 million toward your campaign.