Even before the start of the war in Ukraine, an international alliance to rally the world against a Russian invasion came together so quickly that United States President Joe Biden later marvelled at the "purpose and unity found in months that we'd once taken years to accomplish".
Now, with the conflict in its fourth month, US officials are facing the disappointing reality that the powerful coalition of nations - stretching from North America across Europe and into East Asia - may not be enough to break the looming stalemate in Ukraine.
With growing urgency, the Biden administration is trying to coax or cajole countries that have declared themselves neutral in the conflict, including India, Brazil, Israel and the Gulf Arab states, to join the campaign of economic sanctions, military support and diplomatic pressure to further isolate Russia and bring a decisive end to the war. So far, few if any of them have been willing, despite their partnerships with Washington on other major security matters.
Mr Biden is making an extraordinary diplomatic and political gamble this summer in planning to visit Saudi Arabia, which he had called a "pariah".
On Thursday (June 9), he met President Jair Bolsonaro of Brazil on the sidelines of the Summit of the Americas in Los Angeles. Mr Bolsonaro visited Moscow the week before Russia invaded Ukraine and declared "solidarity" with President Vladimir Putin.
In Los Angeles, Mr Bolsonaro pre-empted any push by Mr Biden on Russia, saying that while Brazil remained open to helping end the war, "given our reliance on certain foreign players, we have to be cautious".
US officials acknowledge the difficulties in trying to convince countries that they can balance their own interests with the American and European drive to isolate Russia.
"One of the biggest problems that we are facing today is the fence-sitter problem," Ms Samantha Power, head of the US Agency for International Development, said on Tuesday after giving a speech about the administration's efforts to reinforce free speech, fair elections and other democratic systems against authoritarian leaders worldwide. Russia's currency, the ruble, cratered shortly after Mr Putin launched the invasion of Ukraine in February. But it has since bounced back as Russia continues earning hard currency from exporting energy and other goods to many nations, including China, India, Brazil, Venezuela and Thailand. For some countries, the decision of whether to align with the US can have life-or-death consequences. Washington has warned drought-stricken African nations not to buy grain that Russia stole from Ukraine at a time when food prices are rising and possibly millions of people are starving. "Key strategic middle powers such as India, Brazil and South Africa are consequently treading a very sharp line in an attempt to preserve their strategic autonomy and cannot be expected to simply sidle up to the US," said Mr Michael John Williams, a professor of international relations at Syracuse University and a former adviser to Nato.
"Washington believes this war will be won in the West," Prof Williams said, "but the Kremlin believes it will be won in the East and the Global South." In a vote in March on a United Nations resolution condemning Russia's aggressions against Ukraine, 35 countries abstained, mostly from the Middle East, Africa and South Asia. That alarmed American officials and their allies, who nonetheless noted that 141 of 193 states censured Russia.
Only five states, including Russia, voted against the measure. Brazil voted to condemn Russia, and Mr Bolsonaro has pressed for negotiations to end the war. But his country continues to import fertiliser from Russia and Belarus, an ally of Moscow.
India and South Africa both abstained from the UN vote. India has a decades-long strategic partnership with Russia and relies on it for oil, fertiliser and military equipment.
The Biden administration has had little luck getting India to join its coalition. During a visit to Washington in April, India's Foreign Minister Subrahmanyam Jaishankar dismissed questions on the subject, saying that "probably our total purchases for the month would be less than what Europe does in an afternoon".
But Europe is now slashing its energy imports, in a partial embargo of Russian oil, while India is reportedly in talks with Moscow to further increase its already growing purchases of crude oil.
South Africa's ties to Russia go back to the Cold War, when the Soviet Union supported the anti-apartheid movement that transformed the nation's internal power dynamics.
Trade between the two countries is modest, but South Africa, like many other nations, has long been suspicious of Western colonialism and the US as an unrivalled superpower.
President Cyril Ramaphosa of South Africa has accused Nato of provoking Russia into war and has called for renewed diplomatic talks.
In a phone call in April, Mr Biden urged him to accept "a clear, unified international response to Russian aggression in Ukraine", according to a White House statement. A month later, Mr Ramaphosa lamented the effect that the conflict was having on "bystander" countries that he said "are also going to suffer from the sanctions that have been imposed against Russia".
The growing urgency in the Biden administration is embodied in the president's plans to visit Saudi Arabia, despite his earlier denunciations of its murderous actions and potential war crimes. Mr Biden's effort, which is already being criticised by leading Democrats, is partly aimed at getting Saudi Arabia and the United Arab Emirates to help on the margins with Ukraine. One goal is to have those nations coordinate a substantial increase in oil production to help bring down global prices while the US, Europe and others boycott Russian oil.
American officials have been disappointed by the proclaimed neutrality of the two Gulf Arab nations, which buy US weapons and lobby Washington for policies against Iran, their main rival.
Israel, which also buys US weapons and is the US' closest ally in the Middle East, has expressed solidarity with Ukraine. At the same time, however, it has resisted supporting some sanctions and direct criticism of Russia.
Until Mr Biden offered to meet him in Los Angeles, Mr Bolsonaro had signalled he would not go to the summit of most of the hemisphere's heads of state. It took a direct appeal by former Senator Christopher Dodd of Connecticut, a special adviser to the summit, to convince Brazil to attend.
Ms Valentina Sader, a Brazil expert at the Atlantic Council, said the Biden administration was expected to continue talking to Mr Bolsonaro about Brazil's ties with Russia and China. But, she said, it was unlikely that Mr Bolsonaro would edge away from Mr Putin.
"Brazil is taking its own interests into account," Ms Sader said.