For pure politics, the half-hour that began around 4:30 p.m. Tuesday was arguably America's most consequential 30 minutes in the last four decades or so. In a federal courthouse in lower Manhattan, the former personal attorney to Donald Trump — Michael Cohen — pleaded guilty to eight felony charges and implicated the 45th president in scheme to violate federal election laws. At almost the exact same minute, 200 miles down I-95, a federal jury in Virginia convicted a former Trump campaign manager, Paul Manafort, on felony charges — also eight of them — in a money laundering and tax evasion scheme.

But here's the crazy part: The real bombshell that could detonate Trump's chaotic 18-month presidency was yet to come.

While news of the dual felony fests was still sinking into the nation's political psyche, Cohen's personal attorney — Lanny Davis, a longtime ally of Bill and Hillary Clinton whose hiring seemed partly aimed at driving Trump completely over the edge — launched a most unusual and, on the surface, rather odd media tour.

Davis' main purpose was to suggest that while Cohen's courthouse admission that he'd conspired with Trump right before voters went to the polls in 2016 to get hush money to two women with whom Trump had affairs may have been a devastating blow, his client knows a lot more stuff that could be more damaging.

How damaging? Potentially very damaging.

Davis told MSNBC's Rachel Maddow on Tuesday night that his client "is more than happy to tell the special counsel all that he knows, not just about the obvious possibility of a conspiracy to collude and corrupt the American democracy system in the 2016 election … but also knowledge about the computer crime of hacking and whether or not Mr. Trump knew ahead of time about that crime and even cheered it on." Previously, Team Cohen had let it leak that the lawyer also had information on advance knowledge by Trump about a meeting that Manafort, his son Don. Jr. and son-in-law Jared Kushner held with a lawyer with ties to the Russian government at Trump Tower in June 2016.

In other words, the Michael Cohen saga isn't over. It's just beginning. Arguably, Cohen and his new guru Davis are practicing an incredibly high stakes "art of the deal" operation — playing off his former mentor Trump against special counsel Robert Mueller, to see who can make the best offer.

What Team Cohen decides to do in the next few days and weeks could decide the fate of the Trump presidency, because even head-in-the-sand Republicans would have a hard time ignoring insider confirmation of presidential collusion with Russia. Meanwhile, other, hopefully-less-likely scenarios — such as Trump pardons or clemency for Cohen or (slightly more likely) Manafort — would trigger the constitutional crisis that could would rip America apart, figuratively and perhaps literally.

Let's look more closely at what Cohen and Davis are up to.

In recent days, news reports made it clear that federal prosecutors in the Southern District of New York — which is running the Cohen probe with aid from Mueller's team — had enough info both about the payoffs to Trump's ex-lovers and unrelated scandals such as income tax evasion to arrest the ex-Trump attorney. That ratcheted up pressure on Cohen to make a deal.

But what happened in lower Manhattan on Tuesday wasn't really a deal. It was just a first step, albeit a pretty large stride. Cohen pleaded guilty to serious felony charges, implicated Trump in the hush money scheme — but has made no promise to cooperate with Mueller going forward. That issue — and what Cohen knows about Russia collusion in the 2016 campaign — is still on the table.

In other words, the plea was a gambit in an ongoing negotiation. And so the purpose of Davis' media tour was to dangle the promise of Cohen's full cooperation both in front of a nation anxious to resolve the scandals that have hovered over Trump from Day One, and, more importantly, in front of Mueller and his lieutenants.

"I know everyone's interested in the same question: What does [Cohen] know, and is it going to be harmful to Trump?" Davis told the Washington Post. "The script that I worked out very carefully so I'm not revealing what Mr. Cohen told me is that I believe that what he knows in some respects regarding the subject of the Mueller investigation would be of interest." Published reports suggest Cohen could be looking at a 3-5 year prison sentence — stiff stuff for a white-collar criminal in today's American oligarchy — and Davis' strategy is clearly aimed at knocking that punishment down considerably.

But what if Cohen and Mueller can't make a deal? There are many variables. Maybe Cohen — who in a much different time said he'd "take a bullet" to protect Trump — harbors enough residual affection for his ex-boss and the people around him that he does the "wiseguy" thing, zips his mouth shut and just does his five years in Leavenworth.

The other possibility that can't be 100 percent ruled out is that Cohen still pines for a pardon, or at least a commuted sentence, from his old boss who now, as president, has near-absolute pardon power. When Lanny Davis dangles hints about all the dirt that Cohen knows about, he's not just sending a message to Bob Mueller. He's also sending a message to Donald Trump.

Indeed, earlier this year when the pressure was building on Cohen and there were early leaks that he might cooperate with Mueller, many pundits interpreted that as a plea for help from the president. But this week, Davis seemed to shut the pardon door completely. "Not only is he not hoping for it, he would not accept a pardon," Davis told NBC's Today. "He considers a pardon from somebody who has acted so corruptly as president to be something he would never expect."

But — as anyone who's seen 30 seconds of Rudy Guiliani's recent blubbering can affirm — at least 70 percent of what you hear on political TV these days is more empty grandstanding than immutable truth. It's hard to imagine that someone like Cohen, steeped in the Trump Way, would turn down a get-out-of-jail free card to spend the next five years with his wife and kids instead.

Let's take a deep breath to contemplate the remarkableness of this American moment.

The current occupant of 1600 Pennsylvania Avenue has just been named as "Individual-1" in a felony criminal conspiracy involving blatant violations of campaign finance laws to pay hush money to a Playboy model and an adult-firm star — with the goal of hiding that information from American voters, in a presidential election ultimately decided by less than 100,000 votes.

In a simpler time, the nightmare of Donald Trump's presidency would have all but ended at 4:45 p.m. on Tuesday with that admission. But that world no longer exists. In an America where Trump has the support of a state-run media called the Fox News Channel — which played the tragic murder of a young woman by an undocumented immigrant as a bigger story than sworn testimony about the president committing crimes — and his rally-goers are hellbent on locking up … Hillary Clinton, it would take more to bring down the Donald. It's going to take whatever else Michael Cohen knows.

Cohen might be able to shed light on more than just the Trump Tower meeting. Remember, the so-called Steele Dossier — which so far has mostly panned out — included a wild but still-out-there allegation that Cohen traveled to Prague on the eve of the fall 2016 election to pay off hackers. And what about the $1.6 million that Cohen helped funnel from under-investigation GOP lobbyist Elliott Broidy to a different Playboy model named Shera Bechard — and suspicions this was really to help Trump?

Of course, Lanny Davis could be bluffing. Truth is truth — sorry, Rudy — but in this caper very few people are telling it. However, what if Davis and Cohen are not bluffing? Evidence that the future president knew what Russia was up to in 2016 would guarantee a Democratic takeover of the House in a tidal wave that would also seem to ensure Trump's impeachment.

A Trump pardon for Cohen or even for Manafort would also probably trigger his impeachment, but a president more hellbent on preserving himself than on preserving the Republic might decide that keeping his two ex-aides silent is worth more than the implosion of 242 years of mostly democracy.

On Tuesday afternoon, when Cohen and Manafort were going down and it came out that one of Trump's earliest supporters, Rep. Duncan Hunter, had been indicted for essentially living off his campaign donations, I kept waiting for the sad piano coda from Derek and the Dominoes' "Layla" to start playing like the memorable scene in "Goodfellas" where the bodies start piling up, the inevitable bloody outcome of unchecked avarice.

Increasingly, we look to Mafia points of reference with Trump more than political ones — because Trump and his henchmen act just like an organized crime family. The other day, the president insisted that his White House counsel hadn't flipped against him because he wasn't a "RAT."

On Wednesday morning, Trump praised — praised! — the just-convicted Manafort in part because he "refused to 'break'" and give information to prosecutors. The president can seem ignorant of even recent American history, but he does seem obsessed with the late Sen. Joe McCarthy. That's probably because he learned so much of his shtick from McCarthy's right-hand man, Roy Cohn, who taught Trump the deny-everything, admit-nothing, fight-with-the-kitchen-sink style of omerta politics that he now struggles to enforce with Cohen and Manafort. It's a mobbed-up style of autocracy that the Founders feared — and yet couldn't quite design their American Experiment to prevent.

All roads lead to danger. The only thing seems clear is that the fate of Trump's presidency may come down to this: What does Michael Cohen know, and when will he spill it?