One issue now dominates political debate within the major Western democracies, and that one issue could now divide the West upon itself: migration.
Donald Trump is trying to ride a tide of anti-immigration feeling to a victory for his Republican supporters in the US mid-term elections in November.
Angela Merkel is hoping to rise above the waves with her shaky German coalition intact, without ceding too much ground to the hardline mood.
New coalition governments in Austria and Italy have brought hardline voices from the fringe of the migration debate into the halls of power.
Australia is battling criticism of its policy of detaining asylum seekers who arrive by sea offshore in camps on Nauru and Papua New Guinea.
Through it all, Western political rifts have been exacerbated by a raucous online debate allegedly amplified by covert Russian propaganda.
Behind the electoral posturing and the weaponized disinformation, there are real trends with real human and real political consequences.
Migrant flows are still high by historical standards, and the UN estimates there are potentially 65 million refugees and migrants on the move around the world.
The UN High Commissioner for Refugees Filippo Grandi has said the problem calls for a comprehensive global solution -- but the mood of the times is more nationalistic.
As scholar Walter Russell Mead wrote in The Wall Street Journal, migration and not the euro is now the ground on which "the European establishment is more vulnerable."
The German public remains broadly pro-European, but is still adapting to Merkel's attempt to absorb more than one million mainly Muslim asylum seekers in 2015.
- Crime down, fear up -
Despite Trump's repeated claims that those migrants are responsible for a crime wave, total crime figures are down in Germany.
But a number of high-profile incidents involving newcomers, including mass sexual assaults, have inflamed public opinion.
"Crime in Germany is up 10% plus (officials do not want to report these crimes) since migrants were accepted," Trump tweeted this week.
Official German figures show crimes down five percent between 2016 and 2017, dropping to their lowest level in a quarter century.
US ambassador Richard Grenell reportedly boasted he wants to "empower" the European right, as the anti-immigrant mood boosted Merkel's opponents.
Now, her Christian Democrats' traditional center-right coalition partner, the Christian Social Union, has threatened to bring down her government unless she closes the border.
For his part, Trump is determined to halt immigration across the Mexican boundary while he builds the wall he repeatedly promised to chanting crowds of supporters.
The issue unites his base at home and now serves him as he feuds with Merkel and offers succor to his friends among Europe's nationalist right.
Under the administration's "zero tolerance" policy, Trump's border agents began separating migrant children from their parents and detaining them in tent camps.
The president's cheerleaders hailed this as a deterrent to illegal border crossing, until shock images and recordings of wailing infants softened the public mood.
- 'Infest our country' -
Trump initially blamed his Democratic opponents and adopted a dehumanizing vocabulary designed to equate the migrants with members of the MS-13 criminal gang, which has links to El Salvador.
"Democrats are the problem," Trump tweeted, emphasizing the electoral importance of migration as a wedge issue before this year's congressional elections.
"They don't care about crime and want illegal immigrants, no matter how bad they may be, to pour into and infest our Country, like MS-13."
But on Wednesday, coincidentally World Refugee Day, Trump backed down, halting the separation of families but insisting "zero tolerance" stays in place.
This may quiet criticism in his own Republican camp that he had gone too far -- but immigration and race will still dominate the mid-term debate.
In Europe, EU leaders have called crisis talks on migration in Brussels on Sunday as the issue causes fresh divisions on the continent.
The stakes are high for centrist leaders like Merkel and her ally, France's President Emmanuel Macron -- and even for the European Union itself. British voters have already chosen to leave the European Union after a Brexit referendum campaign shot through with anti-immigrant sentiment.
Now Italy's new right-wing coalition has already refused to allow a boat carrying 630 rescued migrants to land.
Interior Minister Matteo Salvini, a vocal Trump fan whose far-right League party came to government on the back of the anti-immigrant wave, warned "illegals" they should "get ready to pack" their bags.
Frontline Mediterranean states are demanding that northern Europe take more of the burden in accepting the refugees who land on southern shores.
But northern electorates are loathe to take them.
"For Mr Salvini, raising migration is a win-win-win," Russell Mead wrote.
"He divides the left and unites the right at home; he challenges the elite European consensus; and he establishes himself as a figure of international significance."
Austria's Chancellor Sebastian Kurz, a favorite of Trump's ambassador Grenell, has warned of "catastrophe" and is courting hardliners like Hungary's Viktor Orban.
These are the leaders who feel the tide of history has turned in their favor.