Gary Younge might have examined Portugal alongside Greece in his persuasive argument on what a left party elected to power can do (Syriza’s defeat shows the left needs a plan to sustain power, 12 July). Syriza’s left populism in opposition raised hopes that all Syriza had to do was shout loud enough and the rest of Europe, also constrained by domestic political pressures, would roll over and do what the professors and columnists turned into Syriza ministers insisted should happen.

It is the Boris Johnson approach to Europe – if you shout loud enough the rest of the EU must bow to Brussels-bashing populist ideology. Syriza held a referendum in 2015 which was pure cake and eat it. The campaign slogan on posters and sprayed on every wall in Greece was “No to austerity, Yes to Europe”. Who could not vote for that – rather as if the UK’s 2016 Brexit campaign was based on saying no to the Brussels but yes to staying in the single market?

The early grandstanding by Syriza ministers lost Greece a year of growth at a time when EU nations were finally coming out of the crash decade. Opinion polls show Syriza lost popular support by the end of 2015 and never regained it.

In contrast, the Portuguese socialists cooperated fully with the EU, accepting that some years of fiscal discipline were needed following the years of cheap euros borrowed after 2000, when southern economies drugged themselves on cheap money. The Portuguese also brought in progressive measures, in contrast to Syriza, where unpleasant vindictive prosecutions were launched against former political opponents and special interests were looked after.

Younge is right. A left party, or indeed any party, can win power with populist demagogy, but to govern more serious thought and honesty with the electorate is needed – as we will soon discover under Prime Minister Johnson.

Dr Denis MacShane

Former Europe minister

• Gary Younge’s analysis of Syriza’s defeat provides a strong argument for leaving the EU as a necessary and progressive step in building an alternative to the EU-designed neoliberal organisation of society that has spawned so much inequality and social dysfunction. Younge cites the positions of the then German finance minister Wolfgang Schäuble and the European commission president, Jean-Claude Juncker, in their dealings with the then Greek finance minister Yanis Varoufakis in 2015: “Elections cannot be allowed to change an economic programme of a member state”; “There can be no democratic choice against the European treaties”. These positions underline the structural impediments that member states are faced with if they pose any challenge to the EU consensus.

It is inevitable that a Corbyn-led Labour government would sooner or later come up against similar institutional obstacles to those that crushed the Syriza-inspired opposition to EU-led austerity.

What is perplexing, therefore, is that Labour has failed to mobilise and lead a progressive campaign to leave the EU. Instead it has abrogated this leadership to muddled prevarication and false progressivism among remainers. If ever the Marxist notion of false consciousness were more apposite, it is in relation to Labour’s metropolitan remain supporters who abandoned the party for avowedly remain parties. It would appear that the Labour challenge under Corbyn is destined to be crushed on the altar of the EU – either from remain voters abandoning Labour or by the EU itself if it challenges the EU’s economic programme as part of a Labour government’s democratic mandate.

Russell Caplan

London

• As Gary Younge underlines, the left, which is used mainly to glorious defeats, now also has to grapple with what happens when victories occur. We can see that Syriza didn’t manage to do that. Elected to fight the austerity politics of the EU and IMF when they simply refused to engage, it crumbled and implemented them.

There are two points that Younge passes over. Firstly, not all Syriza MPs did crumble – 25 walked out in opposition to agreeing a bailout in August 2015. Unfortunately they were unable at that short notice to gather enough electoral support to have an impact.

The wider point is that any left advance, to be victorious even in a partial sense, needs to look beyond parliamentary politics and mobilise people power in workplaces and communities. Jeremy Corbyn’s leadership of Labour has sometimes had a sense of that, but it’s not just a tactic to be used from time to time – it’s a strategy to be built.

Keith Flett

Tottenham, London

• Join the debate – email guardian.letters@theguardian.com

• Read more Guardian letters – click here to visit gu.com/letters

• Do you have a photo you’d like to share with Guardian readers? Click here to upload it and we’ll publish the best submissions in the letters spread of our print edition