CONCEDE THAT THE WAR IN IRAQ WAS A MISTAKE You have a case to make that Obama quit Iraq badly (and that he risks doing the same in Afghanistan). But you lack standing to make that case. You endorsed the war, and one of your main foreign policy mentors, Dan Senor, was complicit in the worst failures of the occupation. Admitting that you were wrong is not easy. (Trust me.) But I think voters would respect something along these lines: “Like most Americans I supported President Bush’s decision to intervene in Iraq. That was a mistake. It distracted us from the more important mission in Afghanistan, and on top of that we botched the occupation. But we should learn from our mistakes, not run from them. And President Obama was in such a hurry to get out that he left Iraq in serious danger of a civil war that could do as much harm as Saddam Hussein ever did.”

DON’T RUSH INTO SYRIA A lot of voters — including this one — agonize about how to deal with the civil war in Syria. We are horrified by the humanitarian catastrophe and would rejoice in the downfall of a monstrous regime. But (unlike some of your neocon cheerleaders), we are wary of being drawn into another regional war, or making matters worse by unleashing sectarian reprisals or empowering a Syrian version of the Taliban. Your proposal to arm the rebels carries a real risk that those weapons will be turned on us. Resist the temptation to be too bold: “President Obama is right to be cautious about Syria. It is an immensely complicated, dangerous problem that menaces half a dozen other states in the region. But on Syria, as on so many other problems around the globe, the president’s response to a complicated problem has been to turn away, to play it down. I have no intention of taking America to war in Syria, but the best way to avoid that is not to sit back while the situation deteriorates. As president I will invite Prime Minister Erdogan of Turkey, other NATO leaders and our Arab allies to Camp David for an urgent summit aimed at bringing the Syrian civil war, and the Assad regime, to an end.”

OPEN THE DOOR TO A DEAL WITH IRAN On the subject of Iran’s nuclear program, you have been all bluster. You attacked Obama for offering to negotiate, when it was precisely that willingness — foolishly rebuffed by Tehran — that earned the president sufficient credibility to enlist a broad alliance behind really tough sanctions. In the past you have said Iran should be denied not only nuclear weapons but the right to enrich uranium for civilian uses, a deal-killer. Most important, you sound not just ready to use force, but eager. Now there is talk of one-to-one negotiations. Tell us that as president you would plan to bargain from strength, but bargain seriously. And don’t take civilian enrichment off the table.

APPLY SOME BAIN RIGOR TO DEFENSE Your proudest credential for the presidency is that you have worked in the private sector, turning bloated enterprises into models of efficiency and productivity. The one place you have failed to capitalize on that is our national defense. On the contrary, you have advocated that the military be guaranteed a minimum of 4 percent of our national wealth. You’ve got it backward: “Here’s your money, now what do you need?” The better Romney line: “I will not stint on national security or shortchange the men and women who serve their country. But I will apply the discipline I learned in the private sector to make sure our defense dollars are spent wisely. The U.S. military will be a lean, mean fighting machine.”

COOL IT ON CHINA You wouldn’t be the first candidate to pummel China on the campaign trail and make nice in the White House. But the stridency of your protectionist rhetoric — your promise to formally label China a currency manipulator, clearing the way for a tariff war — makes many of your supporters cringe. O.K., blaming China is a time-tested applause line. But you’ll sound smarter if before you start the spanking you try this: “A prosperous China is good for America. It is a market for our exports, a source of capital, a moderating force.”

In short, I advise you to demonstrate that you understand the world is a complex, unpredictable, subtle and rapidly metamorphosing place. Obama won’t be expecting that. Frankly, neither will I.