Donald Trump and his mouthpiece Rudy Giuliani are right: Collusion is not a crime.

In fact, there is no crime of “collusion” in the US federal code.

There is, however, a law against “conspiracy.”

Conspiracy means that you planned an illegal act with others.  You didn’t have to commit the act. Just planning it is a crime. If the crime was committed and you knew about it then you are an accomplice.

If a person helps to plan the robbery of the Bank of England but is in another country during the actual theft of the gold bullion, they are just as guilty as the hooded gunmen who broke into the vaults.

As well as a law against conspiracy, there is a US law against a federal campaign accepting something of value from a foreign agent.  This can be money or information.

There is also a law against obstruction of justice. That law is breached when a person obstructs , threatens or coerces prosecutors.

And finally, there is the federal election Law which requires candidates for elected federal office to declare all campaign expenditures, including those made to prevent the publication or broadcast of information detrimental to their campaign.

Donald Trump is being investigated for violations of all of the above. And the net is tightening, which could explain why his tweeted protestations of innocence and attacks on chief investigator Robert Mueller are growing increasingly shrill.

This week the public’s mind has been focused on the conspiracy charge because the trial of his former campaign manager Paul Manafort has started in Alexandria, Virginia. Manafort is not on trial for anything involving the Trump campaign. Instead he is charged with a 18 counts related to tax evasion, money laundering and bank fraud. And that is just the current trial. Manafort faces a second trial in September in a Washington DC court at which he is due to be charged with making false claims under the Foreign Agent Registration Act and witness tampering.

Although neither of the above trials directly relates to the Trump campaign,  Manafort is still a central figure in the claims that Donald Trump Jr, Jared Kushner, Manafort—and possibly the president himself—conspired with agents of the Russian government to receive information to help Trump’s campaign against Hillary Clinton.

The claims involve the June 2016 meeting at Trump Tower between the three men, British music publicist Rob Goldstone and several well-connected Russians. The meeting was set up by Goldstone who told Trump Junior that the Russians had some “dirt” on Hillary. “I love it,” Trump Junior tweeted back.

What happened at that meeting, and who knew what when has been the subject of several congressional interrogations, investigations and reports.  It remains central to the Mueller investigation. Did they talk dirt about Hillary? Or did they talk about sanctions against Russia? Or did they, as Trump Junior disingenously initially claimed, discuss the adoption of Russian babies? Did Donald Trump know they were talking?  And finally, does it matter if they actually talked dirt if the Trump campaign went into the meeting expecting dirt?

Manafort knows. But he is not saying. The theory is that Special Prosecutor Robert Mueller, has compiled a list of charges that can put Trump’s former campaign manager in prison for life. And he will drop the charges if Manafort flips and turns on his former boss.

So far there is no sign of a flipped Manafort. This could be for several reasons. He may think he can best Mueller in court. He may be innocent. He may have been promised a pardon by the White House or—given the Russian penchant for murdering political opponents abroad—he or his family may have been threatened by Moscow.

Regardless, the Manafort trial is only the first wave in Mueller’s assault against the White House.  Thirty-two people have been indicted to date. He is slow, methodical, and determined. He won’t give up. No matter how many times the President tweets his demand for Mueller’s dismissal.

* Tom Arms is foreign editor of Liberal Democrat Voice and author of “The Encyclopaedia of the Cold War” and “America Made in Britain". To subscribe to his email alerts on world affairs click here.