Emmanuel Macron’s open letter to Europe’s citizens, published in all 28 EU member states, is an ambitious attempt to stop the rot inside the EU and create a framework for progressive, democratic renewal. But in taking his best shot at saving Europe, France’s president has badly misfired, or – to use a duelling term adapted from the French – deloped.

Europe’s future cohesion and coherence are of primary importance to Britain, in or out. Macron is right to warn that this is a pivotal moment. The corrosive, continent-wide onslaught of rightwing populist, nationalist and xenophobic forces is real and urgent. It found its most recent expression in Estonia at the weekend, where electoral support for the far right surged.

Yet the debate kickstarted by Macron is one from which the English, Scots, Welsh and Northern Irish, apparently against the wishes of most, will imminently be excluded. That is a tragedy for Britain, but also for Europe. EU blueprints of any kind generally benefit from British input, if only in moderating wilder, more impractical ideas. This is the case now.

Macron’s idealistic, statist scattergun approach is most evident in his proposal for a new “European Agency for the Protection of Democracies” whose task, he says, would be to provide member states with expert advice on how to defend elections from outside manipulation. It would also regulate party funding and police the internet.

This sort of invasive attempt to impose supranational controls, overseen by Brussels, on something as democratically fundamental as a national election is why so many people, not just in Britain, have come to resent and distrust the EU. In floating such a top-down idea, Macron betrays a lack of feel for the popular will – and the spirit of the times.

Remainers in Britain who back a second referendum, and would support post-Brexit efforts to rejoin the EU, should consider the implications of this and other aspects of Macron’s “European renaissance”. He seems to mean well. But does he really think Poles, or Greeks, or even the Russian-bullied Baltic republics would trust the EU to be ultimate arbiter of the fairness of their constitutional processes?

Macron does not duck the EU’s most divisive internal problem – migration – but neither is he entirely candid. He concedes that this issue, more than any other, fuels anti-EU sentiment in Italy, Hungary and elsewhere. He calls for more stringent border controls and a common asylum policy. All this would be supervised by another new EU-wide body, a sinister-sounding “European Council for Internal Security”.

Yet recent polling suggests that while majorities in most European countries support asylum for people fleeing violence and war, voters are uniformly critical of the EU’s handling of the refugee issue. If and when the next Syria-scale crisis breaks, it is clear most Europeans would prefer that national governments, not a supranational EU body, set policy and take charge – which, in effect, is what Angela Merkel did in Germany in 2015.

Questions of trustworthiness and competence shed doubt on another key Macron proposal: a mutual defence treaty, increased EU-wide defence spending, and a “European security council”. Although he talks of a continuing association with Nato, this plan looks like a reincarnation of long-simmering, essentially anti-American, quasi-Gaullist ideas about an independent Europe freed from US “hegemony”.

There is much to recommend a more autonomous capability, given the transatlantic uncertainties of the Trump era. But in truth, EU countries remain only too content to shelter behind the post-1945 US defensive shield, continue to limit or cut defence budgets, and have done little in practice to realise French hopes of a European army. The recent, cautious Franco-German treaty of Aachen provided another reality check in this regard.

Europe needs Britain if it is to sustain a credible defence, security and intelligence-gathering posture. Macron knows this full well, which is why – in this respect alone – he signalled willingness to keep Britain “onboard”. This raises the question of why he otherwise appears so keen to exclude Britain. The UK, he wrote smugly, would eventually find its “true place” in relation to Europe – evidently without much help from him.

For Macron, Brexit Britain is most useful as a dire warning of what happens if you challenge his grandiose idea of Europe. The demons are unleashed, the “anger-mongers” take charge, and things fall apart. He is right, up to a point. He is also right when he argues no single country “can act on its own in the face of aggressive strategies by the major powers … Who can claim to be sovereign, on their own, in the face of the digital giants?”

But Macron’s Charlemagne-ish idea of an ever more united, integrated, regulated and collectivised Europe, standing its ground against rival US, Chinese and Russian geopolitical blocs, is strangely outdated – and, given the EU’s many enduring divisions, internal contradictions and structural weaknesses, fated to founder.

It lacks the balance and political grounding provided, hitherto, by the more pragmatic British approach, which promoted a loosely aligned, enlarged alliance of sovereign European states espousing common values and cooperating, when feasible, on matters of common interest.

Macron’s impractical, overblown European vision is not the answer to the threat posed by nationalist regression and populist power-grabbers. In talking to Europe’s citizens, he talks down. Nor is his the kind of EU, if it ever came into being, of which most Britons would want to be a part. Which is why, even at this late hour, it is imperative that Britain abandon Brexit and, once again, help to lead and win the battle for Europe.

• Simon Tisdall is a foreign affairs commentator. He has been a foreign leader writer, foreign editor and US editor for the Guardian