Forget the economy. It's immigration, stupid.

The 2016 equivalent of adviser James Carville's bottom-line guidance to Bill Clinton's election team 24 years ago is more about illegal immigrants, mass deportations and building fences and walls than bottom lines.

Once the purview of fringe protest parties, in the Trump era, promising to keep (or kick) people out has gone mainstream, a common staple of political stumping, and in some places, even a tool to shore up governments.

U.S. Republican presidential candidate Donald Trump has certainly been the megaphone for a message that used to get much less attention than election promises about creating jobs and cutting taxes.

And Trump outdid even himself this week when he vowed to begin deporting millions of illegal immigrants within the first hour of his presidency.

But while he may be the loudest and most outlandish pedlar of such promises, Trump is neither alone, nor the first.

Immigration, illegal or otherwise, has become a cross-Atlantic obsession: obscure citizenship and immigration rules and challenges have become routine subjects for election debates as well as pub arguments.

Barbed wire

Even Trump's aggressively renewed promise to build a wall along the border with Mexico does wilt somewhat in the face of Hungary's popular, anti-asylum seeker, barbed-wire fence, which has been fully operational for more than a year and eminently successful at keeping foreigners out.

Hungarian soldiers stand guard at the Serbian-Hungarian border fence at a makeshift camp near the village of Horgos, Serbia. (Marko Djurica/Reuters) But it's the discussion of an exit strategy from "bad" immigration that is all the rage now. And Trump's bluster is just the topper in what's been a banner week for anti-outsider rhetoric.

Here in the U.K., what was supposed to be a simple meeting of the new cabinet to discuss how to Brexit appeared to devolve into a strategy session for an exit of a different kind.

Theresa May, the newly installed prime minister, reportedly emphasized that curbing immigration must be at the "heart" of a deal for ditching the European Union. Good news for Brexiters, because curbing immigration was also at the heart of the campaign to persuade the majority of the electorate to vote to leave.

In any new deal, the government would seek not quite a wall, but "controls on the numbers of people who come to Britain from Europe," a May spokeswoman said.

Theresa May holds a cabinet meeting to discuss department-by-department Brexit action plans. (Stefan Rousseau/Reuters) Nigel Farage, the British politician who deployed a poster showing a mass of travelling asylum seekers (nowhere near the U.K.) during the Brexit campaign, would be pleased.

Not so much Polish residents of Britain, who this week learned of the murder of a Polish-speaking worker — a crime that many believe was motivated by xenophobia.

The Polish ambassador blamed the anti-immigrant atmosphere that has prevailed following the Brexit vote.

Forced exit

It's little surprise the topic of fending off outsiders is dominating several election campaigns now underway in places like Austria, France and Germany. An unprecedented influx of asylum seekers last year brought the issue to the fore, both in Europe and abroad, and it has remained there ever since.

Insular language has pervaded everything from campaign literature to newspapers, playing to the basic need to be protected, to be sheltered, to keep the elements out.

Except the elements here happen to be desperate human beings.

Nicolas Sarkozy, former president of France, is running for office again. He's focused on immigration. (Charles Platiau/Reuters) In France, immigration was always a central issue for Marine Le Pen of the National Front. While also a hardliner on immigration, former president Nicolas Sarkozy, now a candidate again, is wading ever deeper into the politics of forced exit.

This week, Sarkozy said family reunification policies should be suspended until the EU "comes up with a solid immigration policy for all member states, and does more to protect its border."

He also wants tougher rules for those already living in France: social benefits only after five years, and citizenship after ten years, not five.

The headline from a Sarkozy speech last week was, "Be French or go home."

That same week, there was a less polished suggestion from a Hungarian politician: hang pigs' heads along the border to keep Muslim asylum seekers out.

The fundamental message from such politicians on both sides of the Atlantic is there are those who belong and those who don't. There are good immigrants, and there are bad ones, though those lines are often blurred.

And there are clearly votes to be won in promising to keep out as many as possible.