John McTernan is head of political practice at PSB , a strategic research consultancy. He was a speechwriter to ex-British Prime Minister Tony Blair and served as communications director to the former Australian Prime Minister Julia Gillard. The opinions expressed in this commentary are his own.

(CNN) Do politicians need to be populist to be popular? Since the election of President Trump and the Brexit result in the UK, this has been the question haunting European politics .

I call it "muscular centrism." But what are its distinguishing characteristics?

First, it is politics with a passion. Macron got it just right when he said the second-round battle in France will be between patriots and nationalists.

This is not intended to demean the French voters who supported Le Pen: in a democracy that kind of condescension is wrong. It is, though, a direct challenge to Le Pen's claim that France has to be saved and that she alone is the person to do it.

Contesting that claim vigorously is key to the centrist's success. Contrast it with the bloodlessness of Hillary Clinton's campaign, which ended as a political version of "United Colors of Benetton."

This leads us to the second point: Centrism needs to be confident to succeed.

Macron knows what he stands for and exactly where he stands politically, and he knows that this is where a large part of French society stands politically, too.

JUST WATCHED Macron, Le Pen advance to run-off Replay More Videos ... MUST WATCH Macron, Le Pen advance to run-off 01:40

He is not spooked by the far left or the far right. The strength of centrism is sometimes seen as a negative -- that it is neither one extreme nor the other, so in the hyper-partisan world we now apparently live in, it fails to cut through the chatter.

In fact, its deep and abiding strength is that it can reach both to left and right and give the mainstream majority their voice back. The peril of populism for moderate politicians is that it polarizes debate.

Which leads us to the final point. The program of a successful centrist will be realistic, not modest. This is important as the two are often confused.

In debates, Macron was often isolated. His spending program was smaller than the other main candidates. His cuts to red tape or to the size of government were more pragmatic. In a bidding war, that is a losing hand. But the voters are choosing a leader, not acting as cheerleaders.

Is a victory like Macron's unique to France? No. It can be seen in the victory of now-Prime Minister Justin Trudeau in Canada and is behind the popularity of the Australian Labor Party under Bill Shorten.

But it is not merely the province of the center left. It underpinned the re-election of right-leaning Prime Minister Mark Rutte in the Netherlands and it is powering the Scottish Conservative leader Ruth Davidson in her successful challenge to the dominance of the Scottish National Party.

The success of the Third Way for former President Bill Clinton, former German Chancellor Gerhard Schroeder and Tony Blair, the ex-British Prime Minister, was so great that politicians on the right, including David Cameron in the UK and John Key in New Zealand, triumphantly adopted it.

It has, as yet, had no successor. Perhaps we have one now. Is "muscular centrism" the Fourth Way?