"Free yourselves from your prejudices, from greed, from contempt. Free yourselves, to free society! If you begin to see in each human face, not that which is different from you, but that which is the same, you will become that most incredible of beings: Humanity."

That was the stirring cry of French politician Jean-Luc Melenchon after his left-wing allianceFor this year's legislative elections, four French parties - France Unbowed, the Socialists, the Communists and the Greens - formed an alliance known as the New Ecologic, Social and People's Union, or NUPES. inflicted a stunning setback on President Emmanuel Macron, depriving him of a majority in the National AssemblyThe lower house of the French Parliament, the equivalent of the House of Commons.. 

Melenchon came closer than ever before to the presidency in the elections this year. Now, with 131 seats, his alliance is set to become the official opposition. That could be the platform he needs to secure the top job next time round.

Meanwhile, more than 5,000 miles away, another country felt a seismic shift. In Colombia, Gustavo PetroA left-wing Colombian politician who was once a member of revolutionary militia M-19. He has previously served as mayor of Bogota and as a senator., a former guerrilla fighter, became the country's first ever left-wing president.

Petro plans to reopen ties with neighbouring Venezuela, led by controversial left-wing strongman Nicolas MaduroPresident of Venezuela since 2013. A close associate of his more popular predecessor Hugo Chavez, he has been criticised for ruling by decree instead of through the legislature, and accused of economic mismanagement and repression.. He has pledged to phase out the country's fossil fuel dependency.

The last year has also seen shock wins by left-wing candidates in Peru and Chile, both countries with a historically right-wing political culture, as well as in Honduras. And it is likely that the left will triumph in the Brazilian elections in October.

In the past, Latin America has been a bellwether of global political movements. After World War Two, the dominant economic theory around the world was KeynesianismAn economic theory formulated by British economic John Maynard Keynes. Keynesians favour government intervention in the economy to boost growth., which is associated with centre-left politics.

Then in 1972 in Chile, Augusto PinochetA brutal dictator who seized power in Chile in 1972 with US backing. He murdered, tortured and detained thousands of people. seized power in a bloody US-backed coup. He introduced a new kind of economic policy, known as neoliberalismAn economic and political theory that maintains the government must be as small as possible. Neoliberals favour low public spending and private ownership in the economy.. In the next twenty years, almost every other country in the world began to introduce neoliberal policies.

These right-wing governments were initially popular because they lowered taxes and kept down inflation.

However, their policies also led to enormous economic inequality. The rich mostly benefited from low taxes while ordinary people's wages stagnated.

Now a new generation feels shut out of this economy. Younger voters are finding that the stable, unionised jobs their parents enjoyed no longer exist. Instead, they are stuck in low-paying, precarious work. 

They can no longer afford their own homes. Many end up paying as much as half their income in rent.

Everywhere that the left is sweeping to power, they have been driven by this generation of frustrated young people. Now some think they may push the world into a new era of left-wing politics.

But others are not so sure. They point out that even if the left has scored a few victories, they are still much less powerful than the nationalist right.

It took an alliance of four left-wing parties to reach 131 seats in France. Meanwhile, the right-wing populist National RallyFormerly known as the National Front, the National Rally is a major far-right political party in France. It is accused of being racist and Islamophobic. won 90 seats by itself. For the second time in a row, its leader, Marine le PenThe leader of the National Rally who has sought to moderate its image and normalise its place in French politics., made it to the second round of a presidential election.

Yes: The current order is clearly unsustainable. Too many people cannot get ahead in the economy. Support for left-wing parties calling for it to change will only continue to grow.

No: Left-wingers may be scoring limited victories but they have also been squashed in Britain, the USA, Germany and Spain. Across most of the world, right-populists are still in the ascendant.

Or... The rise of the left is real, but it is likely to fuel the nationalists still further. If they seem like the main bulwark against the left, the centre-right might vote for them just to keep left-wingers out of power.