Updated

Mitt Romney’s six-day trip to Great Britain, Israel and Poland is critical to the nation and the world. The visits give him the chance not only to spell out his foreign policy differences with the incumbent president – something every candidate needs to do – but, more important, demonstrate to the voting public that he has the knowledge, vision and, yes, toughness to guide the nation through a dangerous world.

That makes this trip a great opportunity – but also a great challenge. Romney was aggressive in his criticism of President Obama in his speech before the Veterans of Foreign Wars on Tuesday, but he was short in specifics about what he proposes to do differently. Since the former Massachusetts governor has pledged to refrain from criticizing the president while he is overseas, in keeping with a longstanding American tradition, that puts all the more pressure on him to flesh out what so far are only general statements of principle.

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It’s going to be a high-wire performance. He cannot play into Democratic charges that he is a foreign policy lightweight. But if he says too much, he runs the risk of offending key voting blocs back home – or worse, committing the kind of gaffe that can haunt a candidate on Election Day.

Foreign policy has almost as many facets as there are countries in the world, but given Romney’s itinerary, and given the major global issues now in play, three areas are the most likely for discussion.

Managing relations with Israel and the Middle East: Israel is, of course, America’s indispensable ally in the region, so pledging to support it is not just the right thing to do, it is a moral imperative. But what form would that support take under a President Romney? How far would he go in promoting a two-state solution with the Palestinians? Would he give the green light to more Israeli settlements on the West Bank, which the Palestinians consider a deal breaker, or would he urge restraint?

Romney also will need to clarify what should be done about Iran’s nuclear program, which gets into the question of whether an Israeli airstrike is acceptable to him. Then there is Syria’s vicious civil war, the outcome of which will have consequences for Israel and the region no one can foresee. A lot of Americans will be listening for Romney’s views on these and other issues, especially Jewish voters who have the ability to swing key states like Florida.

Dealing with China and Russia: Many analysts predict China will overtake the U.S. as the world’s No. 1 economy in the not-too-distant future, and Russia is not only developing economic muscles of its own, but flexing them with increasing frequency. In the past, Romney has suggested he would take an aggressive line with both countries, going so far as to call Russia our biggest geopolitical foe. He stopped short of that in his VFW speech. But he may be tempted to talk tough again when he appears alongside Lech Walesa, who led Poland’s successful struggle to free itself from Russian domination. If Romney does engage in hard-line rhetoric, it is an open question how well that plays with moderate and undecided voters.

Steering Europe through its crisis: The visit to London is focused on the Olympics – and a chance to remind folks about Romney’s successful management of the Winter Games in Utah in 2002. But setting foot anywhere in Europe right now gets into the question of the continent’s debt crisis and the teetering economies in Greece, Spain and elsewhere. A European collapse could drag the U.S. down too, so people will be listening for any comments Romney has to offer. It’s a tricky subject to tackle, but a hard one to ignore.

Obama campaign officials will be watching for every chance to pounce on Romney weakness, real or perceived. That is par for the course in politics, but it carries its own set of dangers. Too much gleeful piling on will look like cheap partisanship. Sometimes it’s best just to let the other guy have his turn in the sun.

Robert L. Dilenschneider is founder and chairman of The Dilenschneider Group, a global corporate strategic counseling and public relations firm.