Here is some of what the secretary general of the United Nations did in May: helped coordinate UN responses to the H1N1 virus in New York and Geneva, where he also attended a World Heath Organization assembly and persuaded heads of pharmaceutical companies to donate vaccines; addressed a summit in Bahrain on dealing with disasters; met with Congressional committees to discuss UN funding decisions; visited the last battlefield in the ugly quarter-century war in Sri Lanka and toured a camp for displaced Tamils, then prodded Sri Lanka’s president to hasten relief and reconciliation; urged global business executives in Copenhagen to act on climate change; and held twenty-one meetings in one day with various Danish leaders and environmental experts before moving on to an official visit to Finland.

Secretary General Ban Ki-moon is halfway through his first five-year term in office. Whether he gets another five years will depend not on how many air miles he logs but on what all this activity achieves. From his perspective, he is laying the diplomatic groundwork for shared problem-solving, not looking for instant results. He does not showboat.

Ban, who previously served as the South Korean foreign minister, is all but unknown in the United States. The UN is getting less and less coverage from fewer American reporters at its headquarters. But the United States, as always, will decide the secretary general’s fate. Bill Clinton dumped Boutros Boutros-Ghali after one term when the too-foreign Egyptian was perceived as a political liability. Kofi Annan endured shrill calls for his resignation after branding the US-led invasion of Iraq “illegal” and opening himself to a revenge attack over a corrupt “oil-for-food” program that had fed Iraqis under sanctions. Though cleared of corruption charges by an independent investigation, he suffered considerable physical and emotional damage, and the scandal tainted the final months of his tenure.

Not much is known about the relationship between the Obama administration and Ban, a George W. Bush/John Bolton candidate. But UN officials sense that there are unresolved questions within the National Security Council and between the NSC and the State Department and Pentagon over how to deal with the organization on human rights and international law. President Obama, who as a campaigner talked about marching to the thirty-eighth floor of UN headquarters to announce to the secretary general that the United States was back, has not done that; nor did he endorse the UN with much enthusiasm after he met briefly with Ban at the White House on March 10. But Assistant Secretary General Robert Orr, Ban’s political adviser and an American, says that Ban “has no enemies” in Washington.

The secretary general’s best friends seem to be in Congress, where committees are chipping away at US debt to the UN and have restored contributions to its Population Fund. A new US focus on climate change and clean energy is playing to Ban’s agenda and drawing in environmental activists who might not normally have put much stock in UN leadership. Congressional leaders also appreciated Ban’s reprimanding Mahmoud Ahmadinejad after the Iranian president delivered a vitriolic anti-Israel speech at a racism conference in Geneva this spring.

Ban feels most comfortable and useful in the role of global noodge and pivotal player among nations and nongovernmental actors. A genial man given to informality who has been known to break into ditties or self-deprecating humor at sedate dinners, he is neither a charismatic figure nor a spellbinding speaker. He tries to cement his position a little wonkily through issues, with the world financial crisis sharing the top of the priority list with global warming. That doesn’t attract the personality-driven media, certainly not television (except the BBC). Perhaps this is why he is not infrequently overshadowed by the more theatrical Miguel d’Escoto Brockmann, the General Assembly president from Sandinista Nicaragua, who has brought disgraced capitalism to the fore in a series of large, well-publicized events.

Diego Arria, a former Venezuelan ambassador to the UN (who devised the informal Security Council meetings known as the “Arria formula,” which allow more voices to be heard), says that Ban’s low-key style may be his strength, since most powerful nations prefer a secretary general who does not make himself a strong international figure. Arria also said that a lifetime in the Korean foreign ministry would imbue anyone with a respect for hierarchy and a preference for consensus-building over confrontation.

Ban has dismayed diplomats with a closed-door approach to decision-making that cuts out anyone beyond his inner circle. Experts he consults say they can’t be sure he digests their advice. A European ambassador called Ban’s office “opaque,” and there are persistent complaints from outside the organization that a small coterie of fellow Koreans–the most important of whom is Kim Won-soo, Ban’s deputy chief of staff–appear to be his sole confidants. Ban’s chief of staff, Vijay Nambiar, a skilled Indian former ambassador, vigorously denies rumors that he has considered resigning in frustration.

Ban has made some inexplicable high-level appointments. Thomas Weiss, director of the Ralph Bunche Institute for International Studies at the City University of New York’s Graduate Center and author of a new book, What’s Wrong With the United Nations and How to Fix It, calls the choice of Asha-Rose Migiro of Tanzania as deputy secretary general “puzzling,” given that the office was designed for overseeing internal management and Migiro had no management experience. Fair or not, lapses in UN management are hauled out when isolationist critics go on the attack.

In geopolitics, Ban could still have much to contribute. As the architect of Seoul’s “sunshine policy” of opening to the North Koreans, he could offer insight on the current nuclear crisis. A well-known figure in Asia, he harbors hopes of negotiating the release of activist Aung San Suu Kyi in Burma. His relations with China are good–he speaks Chinese, Japanese and Hindi as well as English, French and German.

Ban may be an unassuming, soft-spoken diplomat, but he is tough when necessary and capable of taking on momentarily thorny challenges (like the latest Israeli-Palestinian crisis) and long-range, new-generation issues (like climate change and global economic readjustment) at the same time, and with a focus on the poorest countries. He was the first international figure to see the damage done in Gaza after the recent Israeli attacks. “He stood in the smoking rubble and said, Just stop now,” his speechwriter, Michael Meyer, recalled. A UN inquiry ordered by Ban found $11 million in often deliberate damage to UN buildings and demanded Israeli compensation. For the rest of this year, Ban will turn to the task of corralling agreement on a still elusive new global pact on carbon emissions. He has been to the Antarctic to see the shrinking ice shelves and will go to the North Pole this summer. He plans a summit-level meeting in New York in September to prepare for a December climate change conference in Copenhagen.

Speaking to the 2009 graduating class at the Johns Hopkins School of Advanced International Studies, Ban said, “This new world demands a special brand of leadership…global leadership…. We need new vision.” He seems to have a candidate in mind for the task.