UN Secretary-General Antonio Guterres marks his first 100 days in office on Monday, facing a long list of worsening conflicts worldwide and still many unanswered questions about where US foreign policy is headed.
The former prime minister of Portugal and head of the UN refugee agency took office on January 1 with a promise to change the United Nations to make it more effective in confronting world crises.
Since then, wars in Syria, Yemen and South Sudan have all taken a turn for the worse, while the administration of US President Donald Trump has imposed the first in a series of potentially crippling funding cuts to the world body.
A suspected chemical attack last week brought a new level of horror to the six-year war in Syria, prompting the United States to fire missile strikes on a Syrian air base in retaliation.
The UN-brokered peace process however remains in a stalemate.
An unprecedented four famine alerts in South Sudan, Yemen, Somalia and northern Nigeria have overwhelmed UN aid workers, with donor funding falling far short of what is needed to avert mass starvation.
Compounding the turmoil are North Korea's missile launches, fighting in Libya, tensions over elections in the Democratic Republic of Congo and the world's biggest refugee crisis since World War II.
Despite the daunting circumstances, there has been praise for the UN leader for bringing new energy to an organization that was sliding towards irrelevance under predecessor Ban Ki-moon.
"He is a much more effective diplomat than Ban Ki-moon, and a much more demanding boss," said Richard Gowan, a UN expert at the European Council on Foreign Relations.
"In a lot of cases, Guterres has been trying to stabilize crises that were running out of control under Ban," he said.
Guterres has traveled to the Middle East, the Gulf region and Africa, personally engaging in behind-the-scenes diplomacy to get leaders to agree on shared priorities for dealing with conflicts.
- Ties with the US -
Despite Trump's dismissal of the United Nations as a "club" where people "talk and have a good time", Guterres has won praise from US Ambassador Nikki Haley, a leading voice on foreign policy in the US administration.
His reforms focus on cutting costs and streamlining the clunky bureaucracy, matching Haley's calls for the United Nations to show "value for the American taxpayer."
The United States is the biggest contributor to the United Nations, paying 22 percent of the $5.4 billion core budget and 28.5 percent of the $7.9 billion peacekeeping budget.
"The more that Guterres can reform the UN system, the more his relationship with the US will improve," said Martin Edwards, a professor of diplomat at Seton Hall University.
"Keeping the Trump administration engaged with the UN, given its rhetoric and lack of direction, is a major diplomatic coup" for Guterres, he said.
One hiccup however came when the White House blocked Guterres's choice of Palestinian Salam Fayyed to be UN peace envoy for Libya, a setback that highlighted how the UN chief's agenda could be hijacked by the United States.
Washington has cut $32.5 million from the UN Population Fund, which provides family planning in 150 countries, and is seeking to draw down and close peacekeeping missions.
Guterres has yet to meet Trump or US Secretary of State Rex Tillerson to discuss how they see the way forward.
Tillerson will pay his first visit to the United Nations on April 28 to chair a Security Council session on North Korea, but no meeting with Guterres has been scheduled so far.