Roger Stone, longtime friend and aide of President Trump, was arrested today in Florida as part of Special Counsel Robert Mueller's investigation. He was charged with witness tampering, making false statements, and obstruction of proceeding.

This is the clearest connection yet between the Trump campaign and the Russian effort to help him win in 2016. The arrest also provides a decently clear glimpse about Mueller's ongoing investigation strategy — namely, get the underlings to roll on the boss.

Here's what Stone allegedly did. He was only formally associated with the Trump campaign for a few months in 2015, but Stone has been friends with him for decades and remained in touch after leaving. After Wikileaks posted the initial batch of emails Russia hacked from the DNC, the Trump campaign allegedly reached out to Stone to see if there were more. Stone allegedly kept in contact with Wikileaks ("Organization 1") through two intermediaries, right-wing crackpot Jerome Corsi and radio host Randy Credico ("Person 2"), and both reportedly kept the campaign abreast of Wikileaks' plans, as well as publicly predicting what they would do on occasion.

When brought before the House Intelligence Committee about all this, Stone then allegedly lied under oath about whether he had communicated with Wikileaks and several other matters. He allegedly tried to convince Credico to lie as well, telling him to do a "Frank Pentangeli" (a character from The Godfather: Part II who does just that). Amusingly, Credico told him to go pound sand: "You should have just been honest with the house Intel committee … you've opened yourself up to perjury charges like an idiot."

The juiciest part of the indictment is undoubtedly this phrase: "After the July 22, 2016, release of stolen DNC emails by Organization 1, senior Trump campaign official was directed to contact Stone about any additional releases and what other damaging information Organization 1 had regarding the Clinton campaign."

Remember by this point it was already well established that Wikileaks got the emails from Russian hackers — but we don't know who the senior campaign official is nor who "directed" them to contact Stone.

As Marcy Wheeler explains, reading between the lines, it appears that Mueller doesn't know (or can't prove) yet who was involved in the campaign's outreach to Stone. Given their extremely long history together and his aggressively cavalier personality, Trump himself is virtually certainly the culprit, but the evidence just might not be there.

Notably, Stone was given the full-on public enemy treatment, with an early morning SWAT team raid and CNN tipped off to film him being dragged out in cuffs. Stone appeared in court looking "disheveled" this morning. Thus this rough treatment — at least compared to the average white-collar criminal; he wasn't beaten senseless or shot outright — gives every sign of being an attempt to coerce Stone into rolling on Trump and anyone else who was involved.

Whether Stone will fold is another question. As Wheeler writes, "I'm not sure that's going to work with Stone." He is a deeply strange and stubborn person who famously has a tattoo of Richard Nixon on his back. He walked out of court after posting a $250,000 bail waving the Nixon V-for-victory salute, and immediately posted a T-shirt for sale on Instagram reading "ROGER STONE DID NOTHING WRONG!" He's just weird enough to stick by Trump.

Nevertheless, Stone is facing serious prison time, particularly over the witness tampering count (as part of which he threatened Credico's dog, which would aggravate the charge). And reading through the indictment, Stone is constantly involved in messy daytime soap-style drama and controversy. It's very easy to imagine two men as petty and vindictive as Trump and Stone somehow getting crosswise and Stone then betraying him out of pique.

At any rate, we'll all find out in court soon enough. At least one thing is clear: The Trump administration and his circle of friends, family, and acquaintances is absolutely lousy with crooks.