Of course, we don’t know yet how comfortably Hillary will work in harness as secretary of state under President Barack Obama. We don’t know if Bill will be able to improve his strained relationship with Obama enough to be trusted with the kind of major diplomatic assignment he would crave. And we don’t know how the world’s most chronicled marriage will play out on the world stage.

But certainly this Featured Return Engagement offers them both a huge opportunity. Preoccupied with economic woes at home, Obama simply won’t have time to spend a big chunk of his first year in office on the road. The crucial restoration of America’s prestige in the world will fall instead to the Clintons.

Hillary Clinton will be an exceptionally knowledgeable and hardworking Secretary of State. She didn’t just visit more than 80 countries as First Lady and senator, she met all the key players and developed a complex understanding of global challenges. Her reputation as a tough-minded hawk will make it easier to bargain from a position of strength. Foreign diplomats aren’t likely to find daylight between Obama and Clinton to exploit. Their substantive differences have always been slight and will grow slighter as Obama’s “team of rivals” becomes, as it did under Lincoln, just a team.

Hillary’s greatest potential weakness is that she isn’t always a good judge of others. This failure to accurately read people can be a serious handicap during negotiations, an area where Hillary has little experience. And, she has shown no sign of being a bold strategic thinker.

If Obama decides to deploy him properly, Bill Clinton will be a terrific troubleshooter, perhaps in tandem once again with his old rival, George H.W. Bush. He could pick up in the Middle East where he left off in 2000. He still knows every street in Jerusalem, every pressure point in the peace process. And it might be worth seeing if there’s anything he can do to bolster civilian leadership in Pakistan.

The former president’s main shortcoming is that he sometimes forgets that he is, well, the former president. Under pressure from Obama, he released the names of donors to his library and to the Clinton Global Initiative (including $10 million from the Saudis), but after promising years ago that his buck-raking days were over, there he was in early December in Malaysia, pocketing $200,000 for a speech. He argues unpersuasively that the $13 million he gave Hillary’s campaign requires that he continue bolstering his ample fortune.

Bill Clinton’s bigger problem is that he can’t let go of his bitterness. Hillary was once the one with the long memory, while Bill forgave quickly. Now the roles are reversed. Hillary is, by all accounts, fully onboard with Obama and looking forward. But well after the election, the former president is still telling virtual strangers that Hillary would have won if this or that hadn’t happened, and he remains privately lukewarm about the president-elect.

Even so, there’s no reason to assume he’ll embarrass Obama and, if he does, White House chief of staff Rahm Emanuel will be on the phone reading him (or her) their Miranda rights. Besides, Hillary knows that all the punditry saying she’s too big to fire is wrong. If she manages to get pushed out, she’s almost certainly finished in politics.

The greater likelihood is success. The Clintons have the rare chance for a “do over” in foreign policy, or, in the case of triumphs like the Irish peace deal, a “do again.” Because they won’t be distracted this time by other obligations, Hill and Bill (the order now reversed) will be able to focus their legendary energies on diplomatic breakthroughs.

More important, the structure of today’s global order may favour Clintonism even more than it did in the 1990s. The Pax Americana of 15 years ago, when the United States stood alone at the summit, was in some ways wasted on Bill, who responded in Bosnia in his first term with a caution befitting a third-string power, not a colossus. Now that unipolar world is gone, replaced by an array of rising powers.

The strength of the Clintons always rested in their ability to grasp subtleties and integrate seemingly disparate issues like energy, counter-terrorism and development. George W. Bush, Dick Cheney and Donald Rumsfeld didn’t “do nuance.” Hillary and Bill do, and they make it pay.

The Obama era has begun, but not at the expense of the Clintons. At a moment of ferment and global possibility, they have more of a chance to shape the world than anyone other than the new president. With so many problems competing for the attention of the new administration in Washington, it’s all hands on deck.