The positions of John McCain and Barack Obama on key domestic issues such as the economy, health care and immigration are likely to determine the outcome of the presidential campaign now about to unfold. More intangible factors – age, race, performance at key events – will be decisive too.

But the next president also needs to be the candidate who can best develop a coherent foreign policy and strategic vision to put the United States back on track as an effective and respected world leader.

The erosion of U.S. strength and credibility in the world under the leadership – more correctly, lack of leadership – of George W. Bush has been that serious. In seven short years, the country has gone from a position of unchallenged superpower to a struggling, diminished nation with an overstretched military, an ineffective diplomatic effort, a seriously weakened economy even more dependent on imported oil, and, perhaps worst of all, more identified with Abu Gharaiblike torture than with the Statue of Liberty.

Still, the history, resources, dynamism and diversity of the American nation give me confidence that we can put this damaging period behind us. McCain and Obama represent two very strong candidates to lead that recovery. Both have exceptional strengths, and the campaign promises to be a dramatic, stimulating contest.

No doubt, negative ads and accusations will whirl away. But McCain and Obama reportedly have agreed to hold numerous debates and discussions – a commitment that will allow a soul-searching examination of the challenges facing the country.

On the international stage, both Obama and McCain must overcome one serious handicap to win support. In Obama’s case, it is his relative inexperience in international affairs. In McCain’s, it is his defense of the war in Iraq, especially his remark that the United States may be engaged there for 100 years.

Here is my checklist of the six most critical issues that face both men.

Middle East-Southwest Asia: Obama has an edge here, mainly due to the disastrous Bush decision to invade Iraq without allies, without sufficient forces, without a plan. But Obama must be more nuanced about withdrawing U.S. forces. Having made this blunder, having undercut the traditional U.S. role as an honest broker in the Middle East peace process, we cannot just depart and allow Iraq to fall into further turmoil, and trigger wider regional unrest.

McCain was foolish to suggest the 100-year commitment, but I’m confident that a man who understands war, could become a Richard Nixon, who sat down with Mao Tse-tung, and can find a way to reduce the U.S. presence so it does not resemble an occupation.

Dealing with Iran, now emboldened by Bush’s failures, is the next major challenge. Bush ignored overtures from Iran when the U.S. was in a strong position after removal of the Taliban in Afghanistan; now his options are narrowing as the U.S. is mired in a country (Iraq) where Iran has significant influence through the Shi’ite population. Far more energetic diplomacy in this region and Afghanistan-Pakistan (see bipartisan Iraq Study Group) is urgent. Advantage: Obama.

Terrorism: Both candidates must define a more effective strategy than Bush’s military-dominated War on Terror. Hard-nosed intelligence and force must be mixed with a wiser use of strategic communications to offset jihadist appeals. There’s a good story to tell, including, among other things, the Bush administration’s huge commitment to global AIDS relief. Advantage: McCain.

Weapons of mass destruction. Proliferation of nuclear weapons remains the most urgent problem to fix, or at least find comprehensive international and regional strategies to control. Handling the nuclear ambitions of Iran and North Korea effectively will be critical. Advantage: Even.

Energy policy: An aggressive policy of research and conservation is overdue. Demand growth in China and India is part of the problem, but U.S. consumption still accounts for up to 40 percent of the world’s energy use. The flow of wealth to oil and gas producers (Iran, Russia) not only empties our pockets, but also undermines our foreign policy clout. Advantage: Obama.

Trade: Perhaps due to a need to counter Hillary Clinton in job-loss states, Obama took overly protectionist positions earlier. The United States cannot move away from free trade. Advantage: McCain.

Global warming: One of McCain’s best attributes has been his independence on many issues – such as election reform and the environment. Obama is already well-positioned on this problem. Advantage: Even.

Absent a major gaffe or “October surprise” that unhinges one candidate more than the other, the most crucial factor in November could be their assessment of “leadership qualities.” When the jurist Oliver Wendell Holmes first met Franklin Delano Roosevelt, he was asked for his impression of FDR. Holmes quipped: “Second-rate intellect, first-class temperament.”

Both qualities, especially if one thinks of temperament embracing sound judgment, are critical in a president. Both McCain and Obama have shown clear traces of both qualities. The next six months should show which one has what it takes in both categories.

Fred Hill of Arrowsic was a foreign correspondent for The Baltimore Sun and worked on national security issues for the State Department. He may be reached at hill207@juno.com.