If a person’s past were another country, Rudy Giuliani, Donald Trump’s lawyer, would be refused a visa.

It takes effort to recall that Giuliani made his name as the scourge of the New York mafia in the 1980s. Today he is under investigation for money laundering, obstruction of justice, campaign finance and other violations by the same US attorney’s office where he made his name.

Giuliani was once a crusader against organised crime and – as mayor of New York – for zero tolerance against the pettier ones. His career is now a byword for the moral descent that characterises public life.

The question is why? Without Mr Giuliani there would be no impeachment inquiry into Mr Trump. It was he who convinced Trump of the alternative theory that it was Ukraine, not Russia, that interfered in the 2016 US election.

It was Giuliani who recruited Gordon Sondland, the US ambassador to the EU, and Kurt Volker, the former US envoy, to press Ukraine to announce a corruption investigation into Joe Biden and his son Hunter. He also orchestrated the smear campaign to fire Marie Yovanovitch as US ambassador to Ukraine.

It is one thing to run a parallel foreign policy as the president’s private lawyer. It is another to extort interference in a US election.

Whatever happens to Trump’s impeachment, the investigation into Giuliani will go on. It is all about how and from whom he gets his money. Since he does not take a fee from Trump, the question is who is paying the piper.

One suspicion is whether it comes from Russia-linked interests. Giuliani has ties to prominent Russian-Ukrainian oligarchs including Pavel Fuks, who once tried and failed to negotiate a Trump Towers in Moscow with Trump, and Dmitry Firtash, an energy billionaire who is fighting extradition to the US on charges of bribery and racketeering.

Giuliani is also mentor to Igor Fruman and Lev Parnas, two Soviet-born businessmen who were arrested last month by the FBI on election finance charges. One of their companies, a cyber security outfit called Fraud Guarantee – yes, you read that correctly – paid Giuliani $500,000 in consulting fees.

Part of the charge sheet is that they donated $325,000 to America First Action, a pro-Trump campaign group, with money channelled from Russia. Campaign fraud on that scale would be a grave offence. Giuliani introduced the two men to Trump, who has been photographed with them several times.

Lobbyist

Another question is whether Giuliani is monetising his access to Trump on behalf of unsavoury foreign interests. Among his clients are Reza Zarrab, a Turkish businessman, who is charged in the US for sanctions evasion with Iran. Turkey’s president, Recep Tayyip Erdogan, wants Zarrab sent home. Giuliani has lobbied Trump to drop the charges.

Another client is the Mujahedin-e Khalq, an Iranian dissident group that was on the US State Department’s terrorist list until a few years ago. Giuliani has written paid opinion articles and given speeches on MEK’s behalf.

Giuliani has not registered as a foreign lobbyist. Failure to do so was part of what landed Paul Manafort, Trump’s former campaign manager, with a seven-year jail sentence. It was also a charge to which Mike Flynn, Trump’s former national security adviser, pleaded guilty.

Many of those around Giuliani should cause any former US attorney to blush. In Giuliani’s case, it is a cause for bragging. As the articles of impeachment are being drawn up, Giuliani is in Ukraine this week making a documentary defending Trump.

All of which is a world away from the New York mayor who was dubbed “America’s Mayor” for his inspirational response to the September 11th, 2001, attacks. Today Giuliani is an American face of “Putinism” – the oligarchic populism that Russia’s Vladimir Putin is exporting to the west.

How does a national hero permit himself to go from there to here? Only Giuliani knows. Faced with a choice between notoriety and losing the limelight, he chose the former. FBI agents hoping to find out more are pursuing a line that the special counsel, Robert Mueller, conspicuously omitted from his Trump investigation: “Follow the money.”

In Giuliani’s case, the money trail is likely to take investigators on a long and exotic journey. – Copyright The Financial Times Limited 2019