So we’ve just passed the fourth anniversary of the day President Bush declared major Iraq combat operations over. This is as good a time as any to ponder what the 44th U.S. president will have to do to reverse the foreign policy mistakes of the 43rd.

This new course isn’t as easy to describe as some Democratic candidates pretend. Chances are President Bush will pass the Iraq dilemma on to his successor in 2009.

But one thing is not in doubt. Poll figures for confidence in President Bush’s international leadership from countries in Europe, Asia and the Middle East are so low that President 44 will have to struggle to reassert America’s global standing.

As Sen. Chuck Hagel, R-Neb., said Monday: “The great challenge of the future will be the reintroduction of America to the world.”

Author and commentator Zbigniew Brzezinski (Jimmy Carter’s national security adviser) takes an interesting look at how the next president might approach that Herculean task in his new book, “Second Chance: Three Presidents and the Crisis of American Superpower.”

Brzezinski faults all three presidents of the post-Cold War era for failing to capitalize on our unique standing as “Global Leader” after the Soviet Union collapsed. Bush I, to whom he assigns a grade of B, failed to take advantage of a swift victory in the 1991 Gulf War to push hard for a Middle Eastern peace accord. Bill Clinton, awarded a C, was wrong to assume that globalization would solve world problems rather than exacerbate tensions.

Bush II, an F, adopted a doctrine focused on unilateral military action, pursuing “a self-declared existential struggle against the forces of evil.” Yet, ironically, his moral certainty wound up undermining America’s moral stature: “The evocative symbol of America in the eyes of much of the world ceased to be the Statue of Liberty and instead became the Guantanamo prison camp.”

Because of Bush mistakes on Iraq, “Our global credibility is shot,” Brzezinski told me, and the world has “lost respect for our power.” So how can President 44 restore America’s standing as a leader, both on the soft-power front – where America leads by example – and as a leader on the military front?

On the soft-power side, Brzezinski believes that globalization of information has made people around the world far more aware of social and economic gaps. The next U.S. president must make clear he grasps the “basic craving in the world for dignity and social justice.” One practical example: fighting hard to expand free trade by cutting U.S. and European subsidies on agriculture that block imports from poor countries. (Brzezinski also thinks we need to address growing economic disparities in the United States that undermine the image of America abroad.)

Another “dramatic issue” is ecology. The next president must not only push to curb carbon emissions at home, but must also seek ways to provide China and India clean energy technology they can afford.

Let me add that, next to Iraq, President Bush’s determined resistance to serious action on climate change is probably the issue most destructive of America’s global image. On Monday, visiting German Chancellor Angela Merkel got no help from Bush on the problem. The best she could elicit – at this late date! – was a belated admission that climate change poses a “serious threat.”

For Brzezinski, the next president must demonstrate the United States is “a genuine partner for the world community and that we are prepared to ask the American people to undertake some sacrifices …” Such as curbing emissions.

On the hard-power side, Brzezinski believes the world still wants and needs American leadership. Europe lacks political unity; Russia is moving backward toward authoritarianism. No one is certain about China’s future.

He wants the next president to work hard to repair our alliance with the fellow democratic nations of Europe. This president would fight Islamist terrorists, but stop whipping up Americans’ fear by using the incorrect term “war on terror.”

“Military power is an important element in the global balance,” he says, “but it has to be done on a collective basis unless it is a last resort.”

And Brzezinski wants Bush to organize serious Mideast regional talks, including direct dialogue with Iran, to stabilize Iraq before we stumble into war with Tehran. “The Middle East has become the test of our capacity for global leadership,” he says.

This is a test that President 43 is failing. In the end, the ability of President 44 to revamp America’s global image may depend on the size of the Iraq mess he inherits from Bush.