“Collusion” is not a federal crime, yet this morning Rudy Giuliani went on CNN to declare his client, President Donald Trump, not guilty of the non-crime of collusion. "Four months, they're not going to be colluding with Russia, which I don't even know if that's a crime, colluding about Russians,” Giuliani said.

I do not think Giuliani is mistaken or ignorant of federal law. (Well, Trump himself might be, but not his lawyers). Giuliani, in the prime of his career, spent nearly two decades as a federal prosecutor. He charged and supervised thousands of cases and, like every other assistant U.S. attorney (I was one once, too), he probably dog-eared his copy of the federal statute book. I assure you, Giuliani knows there is no federal crime called “collusion.”

Here’s why Trump, Giuliani, and others keep using the term “collusion”: it’s good public relations strategy. Giuliani seems to have developed an impenetrable construct: create something that is not a federal offense, and then deny his client committed that non-existent federal offense. He might as well declare President Trump not guilty of the crime of scambaggery . Another tactical advantage of continuing to use the made-up crime of “collusion” is that it raises the bar on what conduct actually does constitute a crime. It just sounds and feels worse than the relatively mundane conduct that can, in fact, constitute a federal crime.

So if there’s no such thing as collusion, then what are we really talking about? It seems the closest thing to what Giuliani means when he talks about “collusion” is the actual federal crime of conspiracy. One federal statute, 18 U.S.C. § 371, makes it a crime to conspire to commit any other federal crime, and many other statutes carry their own sub-parts that criminalize conspiracy, or attempt, as well as the actual completed crime itself.

As with the word “collusion,” people sometimes think a criminal conspiracy needs to be more dramatic than it actually is. People hear “conspiracy” and they think of JFK, Area 51, the moon landing—an evil, secretive plot, a hoax. But don’t misunderstand just how routine, and mundane, a conspiracy can be. As judges instruct criminal juries, a conspiracy is simply any agreement to break the law. That’s it. A conspiracy doesn’t need to be dramatic, or sinister, or clever, or even secretive. It doesn’t even need to be successful. If you and I agree to rob a bank together, take some minimal step towards doing it, and then we fail to pull it off—that’s still a conspiracy.

So, using the actual federal crime that most closely resembles what Giuliani appears to mean when he talks about “collusion,” let’s run down the evidence that could end up dropping the president. Keep in mind, we know only a small fraction of what Mueller knows. Still, the case against Trump starts to come into focus.

The clearest shot at implicating Trump in a conspiracy centers on the June 9, 2016 Trump Tower meeting. We know for sure that Donald Trump Jr., Jared Kushner, and Paul Manafort took the meeting expecting the Russians to offer dirt on Hillary Clinton. After the meeting, Trump, Trump Jr., and others crafted a false public statement that the meeting was mostly about adoption. So, was that meeting, standing alone, criminal? Quite possibly.

If Trump Jr., Kushner, and Manafort expected and agreed among themselves or with the Russians to obtain campaign-related dirt from the Russians, and that dirt had a modicum of financial value, then we have a criminal conspiracy to violate laws prohibiting foreign campaign contributions under 52 U.S.C. § 30121. Further, if the dirt that Trump Jr., Kushner, and Manafort expected to obtain from the Russians involved hacking—a substantive federal crime under 18 U.S.C. § 1030—then we have another federal conspiracy.

“ Giuliani seems to have developed an impenetrable construct: create something that is not a federal offense, and then deny his client committed that non-existent federal offense. ”

Earlier this month, Mueller obtained a grand jury indictment charging 12 Russian agents on precisely those crimes—conspiring, or agreeing, to commit hacking offenses. Similarly, if any person can be tied directly to that already-charged hacking effort—and it appears, at a minimum, that Roger Stone and at least one Republican congressional candidate were involved—then those individuals are liable for conspiracy as well. And if Stone was authorized by anyone inside the campaign, or if the congressional candidate learned about the hacking from somebody inside the campaign, then those people are drawn in too.

Thus, any person who agreed to a plan to receive foreign campaign contributions, or to hack, or to commit any other federal offense, is criminally liable for conspiracy. Giuliani and others might protest that, well, whatever was discussed at that Trump Tower meeting, nothing came of it. No matter. Even if the actual crime(s) never happened, the agreement alone is enough to charge and convict on conspiracy, so long as some minimal step was taken towards the conspiracy (such as several co-conspirators traveling halfway across the world to have a meeting).

Similarly, Trump, Trump Jr., and the rest surely will protest that they never heard of, or met, any of those 12 Russian hackers. Maybe so. But, importantly, there is no requirement in the law that co-conspirators must have known one another, or must have met, or must have spoken directly. In fact, it is not at all uncommon to have co-conspirators who have never met or don’t even know each other’s names. For example, if A ships a load of cocaine to B, who drives the load to C, who sells the drugs to D, then A probably never met D—but they’re both guilty in the same conspiracy. Nor does a participant in a conspiracy have to do much at all. Even one phone call, or one quick conversation, can draw a person into a criminal conspiracy.

The key question, then, will be whether Trump knew about the meeting in advance. If he did, then he almost certainly becomes a co-conspirator. (And Trump Jr., who flatly denied in sworn testimony before Congress that Trump knew in advance, has a perjury problem). Now, simply knowing about a criminal agreement does not necessarily make one a co-conspirator. But if Trump authorized the meeting, or gave a necessary thumbs-up to proceed, then he’s in.

This is why there is so much heat around the claim last week by Michael Cohen’s attorneys that Cohen would testify that Trump knew in advance about the Trump Tower meeting. Few would blindly credit Cohen’s word standing alone, and no fair prosecutor would charge such an important case based solely on the word of a cooperating witness with a shaky history. The question is whether Mueller has enough corroboration to prove up Cohen’s version of events (assuming, for the moment, that Cohen does in fact cooperate, which seems all but certain).

There seems to be substantial corroboration backing Cohen’s claim that Trump knew in advance. Phone records show that Trump Jr. apparently called a blocked number (like his father uses) at key moments leading up to and after the meeting. Three of Trump’s closest advisors—his son, son-in-law, and campaign manager—enthusiastically (“I love it,” Trump Jr. infamously e-mailed before the meeting) met with Russians promising to bring down his campaign opponent, inside Trump Tower. Trump made a mysterious public announcement about forthcoming dirt on Clinton shortly before the meeting happened—the same day that Giuliani now reveals there was a planning meeting to prepare for the Russian meeting. And Trump clearly had some role in crafting the misleading adoption statement after the meeting. Put it all together—and, again, remember that Mueller knows more than we do—and you can see the distinct outline of a federal criminal case against Trump.

So no, Trump won’t be charged with “collusion”—nobody ever has been, Rudy—but a conspiracy charge is absolutely in play.