World leaders faced a full international inbox as they gathered in Hamburg, Germany, for the G-20 summit.

Some crises involved nations not present, like North Korea, Syria and Venezuela. Others concerned countries like China and Russia that are among the group of 20 leading economies. Still others are part of transnational challenges like terrorism, cybersecurity and a global migration crisis.

Tackling these challenges alone is unwise and unlikely. After all, there's little support at home or abroad for U.S. unilateralism, and global crises are best met with multinational responses. So coalitions need to be cobbled together, and such diplomatic craftsmanship requires respect.

Candidate Donald Trump seemed to sense the imperative of improving the world's view of the U.S. when he said in his first foreign-policy speech last April, "And always — always, always — we must make, and have to look at it from every angle, and we have no choice, we must make America respected again."

But as president, Trump has presided over the opposite effect, according to a new Pew Research Center poll headlined "U.S. Image Suffers as Publics Around World Question Trump's Leadership."

A median of only 22 percent of citizens in the 37 nations polled expressed "confidence in Trump to do the right thing when it comes to international affairs," compared with the 64 percent who expressed confidence in former President Barack Obama toward the end of his term.

Only two nations gave Trump higher marks than Obama: Support soared in Russia, with a 42-percentage-point increase from 11 to 53 percent, and it rose more modestly in Israel, from 49 to 56 percent.

Citizens in the other 35 nations expressed less confidence.

A lot less in Sweden, where a dizzying drop of 83 percentage points from 93 to 10 percent reflects Western Europe's deep unease with the change in U.S. leadership. Similar slides were seen in the Netherlands and Germany (each down 75 percentage points), France (falling 70 percentage points), Spain (off 68 percentage points) and Italy (down 43 points).

Even Poland, where Trump received a rousing welcome, was off 35 percentage points, with only 23 percent of Poles expressing confidence in the president.

This split between the U.S. and other NATO nations may make it harder for European leaders to unify their citizens around responses to Russian revanchism as well as other challenges, said Nicholas Burns, director of the Future of Diplomacy Project at Harvard.

Burns, who was U.S. ambassador to NATO on 9/11, recalled how on Sept. 12 Europeans proactively came to him offering to invoke Article 5 of the NATO treaty, the only time the mutual-defense clause has been activated.

He was also around when Europeans turned against U.S. policy — and former President George W. Bush — on Iraq.

And yet, Burns said, "I can't remember a time when the United States has been nearly universally disregarded in these public opinion polls. The tangible problem is that we are still the most powerful country in the world in nearly every respect — political, economic, military, diplomatic — but you still need to be able to persuade countries sometimes to do the difficult things."

Like countering Pyongyang's provocations. But the leader with the most clout to curb North Korea, Chinese President Xi Jinping, who has frustrated administration officials with his ineffectual response to the crisis, polled higher worldwide than Trump in inspiring confidence "to do the right thing regarding world affairs." In fact, of the four leaders considered, Trump rated even behind Russian President Vladimir Putin (German Chancellor Angela Merkel finished first).

And even among allies alarmed over North Korea's weapons development there is doubt: South Korea had the fourth-largest decline in the Pew poll (off 71 percentage points), with only 17 percent expressing confidence in America's president. Japanese support was slightly higher at 24 percent, but that was off 54 percentage points from the end of the Obama years.

Trump's unpopularity has personal components: 75 percent agreed he is "arrogant," 65 percent "intolerant" and 62 percent even consider him "dangerous." (To the president's credit, however, 55 percent also think of him as a "strong leader.") But the unfavorability is also rooted in policies, ranging from Iran to the travel ban, and in particular withdrawing from the Paris climate accord (71 percent disapprove globally) and from free-trade agreements (72 percent disapprove) as well as his plan to build a wall between the U.S. and Mexico (76 percent disapprove, and at 5 percent Mexicans rated Trump lowest in Pew's survey).

There's still a reservoir of goodwill for U.S. citizens and institutions: 58 percent have a favorable impression of Americans, while 65 percent say the same about "American music, movies and television." But what should be our best export — ideas — gets lower marks: Only 43 percent like "American ideas about democracy" and only 36 percent say "it's good that American ideas and customs are spreading here."

Burns said the Pew poll "is shocking because it shows the depth of opposition." And for those unconcerned about global opinion about the U.S. or its president, he reminds Americans that for economic and diplomatic reasons it's in their best interest to care.

"Most Americans understand this very well — we live in a very different world than we did five or six decades ago, even three or four decades ago," Burns said, stressing the need for counterterrorism cooperation as well as cohesion on other essential challenges. "We can't live alone in the world, and we have to rely on other countries to help us deal with these problems. And we certainly shouldn't want all this to fall on our shoulders."

Trump was elected pledging "America First." But if he's last in rankings of major world leaders and has lost the confidence of key constituencies worldwide, it will be challenging for the president to fulfill his promises. So it's in his, and the nation's, best interest that he improve his international standing.

John Rash is a Star Tribune editorial writer and columnist. The Rash Report can be heard at 8:10 a.m. Fridays on WCCO Radio, 830-AM. On Twitter: @rashreport.