WASHINGTON — I traveled with my family in Australia for three weeks as a guest of the Universities of Sydney and Melbourne, invited to explain what’s happening in President Trump’s America.

As if there were an explanation.

Of more interest was what I learned from the Australians. To visit this stalwart ally and talk with its people was to see how the United States, in the space of just a few months, has utterly lost its moral authority.

You see it at the street level: Off Sydney’s Circular Quay, where, just down the street from the felicitously (if coincidentally) named Trumps Alto Ego salon, Trump look-alikes wearing orange wigs and too-long red ties amuse passersby with boorish antics; on Melbourne’s Hosier Lane, a street-art haven now featuring a mural of children throwing rocks at a tank emblazoned with Trump’s scowling face; and even in little Port Douglas in the tropics, where anti-Trump graffiti is spray-painted on the trash bin in the marina.

You see it, too, in only slightly more diplomatic terms, at the highest levels:

Paul Keating, the former Labor prime minister, declared in response to Trump’s election that Australia should “cut the tag” with the United States.

Penny Wong, shadow foreign minister for Labor, which is favored to win the next election, wrote that Trump’s views are “counter to what are core values for most Australians” and suggested Australia orient itself more to the Asia-Pacific region.

Malcolm Turnbull, the prime minister, asserted last month that the “U.S.-anchored rules-based order” can no longer be “taken for granted.” Turnbull said foreign policy should be determined by Australia’s interests “alone.”

It isn’t just rhetoric. In late June, Australia, one of the coalition partners in Syria, suspended air operations over that country after the U.S. military downed a Syrian jet.

Simon Jackman, chief executive of the U.S. Studies Centre at the University of Sydney, sees a dramatic rethinking in the country about the United States. Australians, he says, are asking: “So why are we so close to this country again?”

There were already differences on gun laws (Australia’s are strict) and inequality (Australia is more egalitarian). But Trump has pushed forward on a new set of issues that offend or frighten Australians: building a border wall, abandoning the Trans-Pacific Partnership trade deal and the Paris climate-change accord, trying to take away health insurance from millions of Americans (Australia has universal coverage) and making noises about war with North Korea. “The changing U.S. domestic policy leads people to believe our military policy ought not to be so closely entwined with America’s,” says Jackman.

Polling by the U.S. Studies Centre finds that in the past two years, the number of Australians who say the United States has the most influence in Asia has dropped by half. More Australians see the United States as a force for harm in the region and in Australia than they did two years ago.

Trump is the reason. When a half-sample of poll respondents were asked the U.S.-influence question with the phrase “now that Donald Trump is president” inserted, negative responses jumped 20 percentage points. Similar results were found in Indonesia, Japan and South Korea.

This is consistent with the Pew Research Center poll of 37 countries released while I was down under. A median 22 percent of those surveyed have confidence in Trump to do the right thing in international affairs, down from 64 percent who had confidence in Barack Obama. The percentage abroad with a favorable view of the United States has fallen by 15 points. Some of the sharpest drops were among allies.

This will have consequences. Canadian Foreign Minister Chrystia Freeland says that America’s questioning of “the very worth of its mantle of global leadership puts in sharper focus the need for the rest of us to set our own clear and sovereign course.” And Germany’s Angela Merkel memorably said in reaction to Trump that Europe must “take our fate into our own hands.” This became only more clear after the recent Group of 20 meeting, where Trump was the sole dissenter on the Paris accord and his protectionist talk set off fears that a trade war was forming.

Allies’ alienation from the United States will increase, I suspect, when they come to realize what they’ve seen over the past six months is unlikely to change soon. At almost every stop in Australia, I detected an innocent optimism that the Trump effect would be short-lived: How long until he’s impeached? Can’t he be removed on grounds of insanity? Surely his fellow Republicans won’t tolerate this for long?

I wish I could have reassured them.

Follow Dana Milbank on Twitter, @Milbank.(c) 2017, Washington Post Writers Group

Dana Milbank, Washington Post Columnist