Why is there no mop-haired demagogue here denouncing immigrants as rapists?

After all, if America's excuse is anxiety caused by a flood of incoming foreigners, Australia should be twice as anxious. In the United States,14 per cent of the population was born elsewhere, near the record of 15 percent reached a century ago.

In Australia, more than one-quarter of the population is foreign-born, and some 46 per cent have at least one foreign-born parent, according to the Australian Bureau of Statistics.

Yet both main parties, the center-right Liberals and left-leaning Labor, are committed to continued immigration. Politicians who seek to whip up or exploit anti-immigrant prejudice are relegated to the fringe. Is there some secret sauce whose recipe the United States could copy?

First, a few caveats. One week Down Under does not quite qualify me as a full-fledged Australianist, but it is long enough to learn that this nation of 23 million people is not a race-blind paradise.

Successive waves of immigration have each aroused anxiety among some Australians that the newcomers would never fit in: Greeks and Italians in the 1950s, Vietnamese in the 1970s, Chinese, Indians and Middle Easterners today. People fret over crime and worry that newcomers segregate themselves in suburban enclaves.

Everyone swears fealty to the national ideal of "multiculturalism," but beneath the surface there is profound disagreement over how much assimilation is desirable. Meanwhile the captains of industry and government remain mostly Anglo (and male).

And a sizable share of immigrants continue to come from New Zealand and Great Britain; the country as a whole remains overwhelmingly white.

Still, given that White Australia was official policy until the early 1970s, acceptance of a world in which Chinese and Indians represent the fastest-growing groups of immigrants would strike anyone escaping from the GOP primary debates as remarkable.

Paul Kelly, a leading historian and political analyst with the newspaper The Australian, explained that the nation as a whole realized after World War II that it had to "bulk up" its population if it was to defend itself in a dangerous world. Seven million people in a nation the size of the continental United States wasn't enough - and when it became clear, with time, that Great Britain couldn't furnish enough immigrants, "the White Australia policy buckled, surrendered and was abolished."

"It was a deliberate, bipartisan decision," Kelly told me. "We had to embark on this immigration project to make the nation tenable and viable."

A second critical factor has been Australia's ability to decide who gets in. "The island culture is fundamental," Kelly said. "We control our destiny."

Australia has consistently been a leader, in per capita terms, in accepting refugees from conflict zones. But in 2001, when people from Afghanistan and elsewhere started turning up as boat people, it challenged Australia's sense of control and became "a very traumatic issue," Kelly said.

A conservative prime minister decreed that no boat people would be admitted and was excoriated by human rights advocates. A Labor prime minister in 2007 reversed that call, but when leniency seemed to encourage more and more arrivals - some 30,000 over several years - the nation returned to a no-entry policy. Quickly the boats stopped coming.

Understandably, a policy of turning back asylum-seekers at sea continues to disturb many Australians. But Tom Switzer, a conservative commentator and research associate at the United States Studies Centre at the University of Sydney (which was also my host last week), argues that the tougher policy was not only more humane - because so many migrants were drowning during the years of laxer control - but also essential to preserving public support for legal migration.

"Strict controls help dampen down xenophobia, and ensure that decent treatment is given to those seeking the nation's hospitality," Switzer wrote recently in the Spectator.

In Europe, a sense of helplessness does seem to be fueling xenophobic political forces. A senior German official recently told me that the hundreds of thousands of migrants pressing to enter represent the greatest challenge to the continent since World War II. One reason, he said, is the feeling of being out of control; bordering nine nations, Germany seems challenged to define any terms of entry.

The same logic has helped shape U.S. immigration policy under presidents George W. Bush and Barack Obama, both of whom have emphasized border security, deportation and other enforcement measures in part to lay the political groundwork for humane immigration reform.

The policy has been successful in tamping down illegal immigration, and maybe also in shaping public opinion; polls show a majority of Americans, and even of Republicans, favor a path to legalization for the 11 million immigrants in the country illegally, rather than the mass deportation Donald Trump advocates.

Sadly, though, the enforcement success has yet to produce any Australian-style bipartisanship on this issue out of Republican membes of Congress or presidential candidates. If there's a recipe for that, no one here has shared it with me.