In the old days, these things were done differently. There were KGB couriers, bags of cash, “Moscow gold,” secret subsidies for far-left printing presses: The Soviet Communist Party was seeking to undermine Western democracy, covertly. But it was all pretty small-scale. The U.S.S.R. was not rolling in wealth, and it was never in a position to make its supporters wealthy. Being men of ideology, they weren’t supposed to want money in any case.

Modern Russia, by contrast, has a far easier task. Nowadays, when the Kremlin makes a covert effort to exert political influence and undermine democracy, it has far more tools available — big companies, rich oligarchs, both of which need to keep in with the government — and far more psychological leverage. Instead of the brotherhood of mankind and the unity of the proletariat, modern Russia can appeal to a much simpler instinct: greed. Instead of offering small bits of cash or secret bank accounts, they can now offer deals with friendly Russian businessmen. These are legal, they can be discussed openly, and they create the right atmosphere for friendly relations, even if they never happen.

That’s the background to the curious story of Russian influence unfolding in Britain over the past week, thanks to the revelation of a cache of documents, including email exchanges, published recently in both the Observer and the Sunday Times. The main character, Arron Banks, was the most important funder of the pro-Brexit UK Independence Party (UKIP) as well as Leave.EU, one of the organizations that campaigned to persuade the British to leave the European Union. Banks invested $11 million of his own money into both of those causes and raised an additional $5 million. These are big numbers in U.K. politics, where there is nothing like the spending circus so familiar to Americans.

But where did that money come from? Banks has always said it came from his insurance business, which doesn’t appear to make as much money as he says it does, as well as “diamond mines” he owns in Lesotho, a proposition that at least one scientist says is “geologically impossible.” Now it also appears that Banks, who is married to the daughter of a Russian state official, may have sought business advice further east. On at least one occasion — he and his colleagues visited the Russian embassy multiple times — the Russian ambassador to Britain, Alexander Yakovenko, offered to help him set up an investment in some gold mines in Siberia.

Banks denies that anything came of it. But this curious revelation is interesting on a number of levels. For one, it provides yet another link in the chain of common interests that ties together the Russian government, Banks, the Brexit campaign and UKIP leader Nigel Farage — Farage being a man who has, in turn, links to Julian Assange, Stephen Bannon and Donald Trump. Much more interestingly, it also illustrates how the modern Kremlin political influence machine operates - legally, and without necessarily incurring any government expense.

When the Russian government sought to cultivate a former German chancellor, Gerhard Schroeder, there was no need for the government to sneak him bribes. Instead, state companies, and companies close to the state, offered him an outsized role in the Russian energy industry: directorships, board memberships, contacts. When the Russian government sought to cultivate Italy’s pro-Russian League, one of the two parties that now constitute the strange far-left/far-right Italian government coalition, the lines of contact similarly went through private channels. The Lombardy-Russia Cultural Association, affiliated with the party, has, for example, offered to help broker contacts for Italian businessmen in Russia, and sponsored investment conferences involving Matteo Salvini, the party leader, as well as Crimean officials.

“Let us introduce you to some useful business contacts” was also, it seems, one of the ways in which the Russian government kept the attention of the Trump family. Even as late as fall 2015, with the presidential campaign well underway, the Russian-born businessman Felix Sater was seeking to broker the construction of Trump Tower Moscow. The goal, he told Trump’s lawyer, was both political and personal: “Help world peace and make a lot of money, I would say that’s a great lifetime goal for us to go after.“Also, he would help get Russian President Vladimir Putin on board with the project, see what could be done to help with the campaign: “Our boy can become president of the USA and we can engineer it.” The corrupt implications explain, presumably, why special counsel Robert Mueller has subpoenaed all of the papers surrounding that deal.

Trump Tower Moscow was never built, of course, and it seems that Banks didn’t invest in the Siberian gold mines, either. But they do reveal the Russian government’s modus operandi. Contacts are offered. Connections are made. Some deals go through. Others are dangled, perhaps to keep everyone interested in ongoing relations. Maybe someone will help you win your election, maybe not. Anyway, if you play your cards right, your business will prosper — and you might even get rich like Schroeder when you leave office. Just because it’s legal doesn’t mean it’s not corrupt.

Anne Applebaum is a Washington Post columnist, covering national politics and foreign policy, with a special focus on Europe and Russia. She is also a Pulitzer Prize-winning historian and a professor of practice at the London School of Economics. She is a former member of The Washington Post’s editorial board. Follow Anne on Twitter @anneapplebaum.