Michael Cohen
Former Trump attorney Michael Cohen
The moving train wrecks involving the trials of US President Donald Trump's one-time campaign chief Paul Manafort, and his former lawyer and fixer Michael Cohen, remind us to think carefully about our choice of words.

I'm pondering "collusion". Is it the right word for whatever has been going on?

Eerie echoes of the Richard Nixon-Watergate era resound in this saga. As in Watergate, these are two of the president's men. Nixon proclaimed, "I'm not a crook." Trump proclaims, "No collusion." People again speak of impeachment.

For all its usage, collusion has not yet appeared in any charge. There was no mention of Russia's alleged "collusion" during the Manafort trial, as the charges predated Trump's campaign.

Any prosecutorial lapse regarding "collusion" could yet be filled. Lurking behind the Manafort and Cohen prosecutions is the reported effort by Russia (and, possibly, helpful third parties) to interfere in the 2016 presidential campaign between Trump and Hillary Clinton, and to hack the election process itself.

Special Counsel Robert Mueller's investigation centres on the alleged Russian involvement, plus any other crimes revealed along the way. His prosecutors based their case against Manafort, an international political consultant, on evidence that he misled banks to obtain loans and concealed money overseas.

The prosecutions of Manafort and Cohen focused on their respective financial manipulations. Two criminal charges against Cohen were election-related.

The jury found Manafort guilty on eight charges involving the filing of false tax reports, not filing on a bank account overseas, and bank fraud. Only a single juror prevented a guilty finding on all 18 charges. The judge declared a mistrial on the 10 remaining charges, but the prosecution can seek a retrial.

Or, they could wait for a couple of weeks until Manafort faces a second trial on similar charges. Meanwhile, he can weigh the benefits of flipping - turning government witness - while recalling the days when he earned million-dollar fees and sported the ostrich-skin jackets that prosecutors showed to the jury.

Trump has criticised the prosecution, calling Manafort - who remained silent - a good person. Trump has also said that flipping should probably be illegal.

Unlike Manafort, Cohen flipped. He pleaded guilty to five counts of tax evasion, one count of making a false statement to a bank, and campaign finance violations involving hush-money payments to two women who said they had affairs with Trump before he entered politics. The campaign finance charges were criminal acts.

Cohen admitted to buying the silence of Stormy Daniels, a porn actress who said she and Trump once had an affair. He also admitted arranging the silencing of Karen McDougal, a former Playboy bunny. The National Enquirer , a pro-Trump tabloid, paid McDougal for the story rights but never published it.

Cohen was admitting to campaign finance violations because the payments were made to influence the election results. He told the court he acted "at the direction of the candidate", meaning Trump. The judge asked Cohen if he understood the possibility of imprisonment for up to 65 years. Cohen gulped and said yes.

Whether Cohen is entirely out of the legal thicket might depend on what else the Mueller investigation turns up, and on whatever else Cohen, who has his own Russian connections, can offer Mueller.

A prison term stretching into his dotage should provide Cohen with food for thought. If he knows anything Mueller might find useful, it's time to cough it up.

Some very Watergate-type questions await answers, such as "What did people know, and when did they know it?"

Which brings us back to whether what Trump has repeatedly denied - collusion - is the appropriate term. Picking the right word, as Mark Twain once said, is no small matter. Catching a lightning bug is one thing, but catching lightning is quite another.

In a legal sense, collusion is an agreement between two or more people to defraud someone else of their rights, or to obtain something otherwise prohibited by law.

Collusion originally meant secret agreement or cooperation. The related word "collude" combines the Latin col- (with, or together) with ludere (to play). Collude connotes secret agreement or cooperation, always in a bad way.

Then there's conspiracy - which literally means two or more people breathing together. We use it to mean individuals, secretly acting in concert to commit an unlawful or harmful act. One reason conspiracy theories abound is because they are so easy to confect, hard to prove and, by their nature, even harder to disprove.

To prove that Trump and Russian leader Vladimir Putin colluded would require showing they'd secretly agreed to deny Americans a free election to achieve an outcome.

Alternatively, we could try to show conspiracy, but that, too, is hard to prove, especially when meetings have no witnesses or notes, like those between Trump and Putin, or Trump and North Korean leader Kim Jong-un.

Then, there's "connive" - the willingness to secretly allow or to be involved in an immoral or illegal act. Connive comes from Latin for winking and French for shutting the eyes. In short, doing something with a wink, a gesture, or simply looking the other way. It's a fine old word.

Think of Marlon Brando's Godfather, Don Corleone, eyelids weary and brow furrowed, growling: "Michael, Paul ... You know people ... take care of this."

That's connivance. That's catching lightning in Mark Twain's bottle. That's Trump.

Collusion? The jury's out.