There’s nothing like a US presidential election cycle to prompt British pundits to think about Anglo-America as a “thing”. The UK is the 51st state in all but name, right? In reality, the similarities are more complex, and the differences are stark.

You can understand where the idea comes from. On both sides of the Atlantic 40 years of Reaganite and Thatcherite policies of financial deregulation, union emasculation, and a sanguine attitude to de-industrialisation, have sculpted Anglo-American society in similar ways: declining life expectancy among those whose communities destroyed as a consequence of these policies; and a surviving population that blames immigrants for their problems.

The political response to these economic and social conditions has been the election of two unsuitable philanderers, Donald Trump and Boris Johnson. Both were initially resisted by party elites, who then abjectly surrendered. All dissenters have been purged. Their advisers are bizarre, comic book villain-types such as Stephen Miller and Dominic Cummings.

However, the differences between Labour and the Democrats remain profound. The sudden revival of Joe Biden’s fortunes is proof. Both parties are lazily described as being of the “left” but really, America hasn’t had a “left” in the British sense as long as I’ve been alive, which is a very long time.

The Labour party was from its inception a socialist party, and even though clause IV was taken out of the party’s constitution the ideology of public ownership runs strong in the membership and recent leadership of the party. The “left” wing of the US Democratic party embraces the legacy of Franklin D Roosevelt’s New Deal – but while his opponents in the 1930s called it “socialism”, it wasn’t. Actual socialism never found a foothold in the US – perhaps because it was commonly called “godless socialism”, especially in the south. America is a damned religious country. And Americans have traditionally had no problem with billionaires – perhaps because many of them fervently believe in the American myth that anyone can get rich if they work hard enough. The tragedy of Bernie Sanders is that he is a New Deal Democrat but insists on calling himself a socialist. You don’t win in America using that language. The sudden revival of Biden’s fortunes is proof.

Then there’s the governmental structures these political forces operate within. In Britain, the executive is housed in the legislature. Johnson leads a well-whipped majority and a prime minister with a majority of this size is in charge of an “elective dictatorship”. In the US, the executive branch of government is separate from the legislature. This check on presidential power is profound, especially when, as is the case now, one of the branches of Congress is in the control of the opposition party.

‘Zac Goldsmith, who was elevated to the Lords – and returned to the cabinet – after losing his seat in the last election.’ Photograph: House of Lords/PA

Barack Obama found that out when he tried to appoint Merrick Garland to the supreme court and the Republican-controlled Senate, which has the constitutional role of approving high court judges, would not give Garland the courtesy of a hearing. Trump found the limits to his power when the Democrats took over the House of Representatives and tied him up in impeachment.

The Senate, unlike the House of Lords, is not appointed. It is elected. Senators need to pander to voters successfully, unlike for example, Zac Goldsmith, who was elevated to the Lords – and returned to the cabinet – after losing his seat in the last election.

Then there is money. In the US there is tons of it surrounding elections. Unimaginable sums, really: $6.5bn was spent on the 2016 presidential election across all races, with most of that money going on broadcast media advertising. There has always been money in American politics, but in the past decade it has grown to narco-trafficker levels of cash.

In 2010, the supreme court decided – in the case titled Citizens United v Federal Election Commission – that corporations had first amendment rights – free speech rights, like individuals – and putting restrictions on corporations giving money to air political advertisements in broadcast media was an infringement of that right. Since then the cash has flowed in and Americans are bombarded with paid political propaganda non stop.

In the UK there is no first amendment and there are firm restrictions on political advertising on television and radio. Party political broadcasts are strictly rationed and election campaigns take place within tightly defined windows. But there is a “free” press. Conservative politicians don’t need to raise money for advertising, they get it for free. Every day, outside every newsagent, there is a rack of blaring headlines trumpeting Conservative policies or viewpoints. They’re not far off the billboards that line US highways. Decades of exposure to them, and it’s no wonder that Brexit won.

Clearly, when it comes to propaganda channels, both countries have them, which brings me back to where I started: Anglo-America. Maybe some day Anglo-America will be a reality – after Brexit negotiations collapse, and the UK disintegrates, and England applies to become the 51st state. Then American politics and English politics will be the same. But that will not happen this electoral cycle or the next. The US is still a very, very different country.

• Michael Goldfarb is the host of the podcast FRDH, First Rough Draft of History