(CNN)Donald Trump's once cool relationship with the Republican Party has turned ice cold.
Declaring that the "shackles" of moderation had been shed, Trump on Tuesday unleashed a barrage of angry tweets denouncing the party that made him its presidential nominee, while taking potshots at its leader, House Speaker Paul Ryan.
For nearly 16 months, Trump and Republican officials have maneuvered and played each other, launching and squashing a series of feuds as the party sought to manage Trump and he angled to keep its organization in his corner.
But four weeks out from Election Day, in the wake of two disappointing debate performances and the publication of a potentially campaign-killing video tape, with prominent elected officials fleeing his shadow, Trump is on the warpath again -- and this time, the damage could be permanent.
Here's a look back at how we got here.
August 6, 2015 -- Division at the first debate
In the same city where he'd accept the nomination a year later, Trump at the first GOP primary debate in Cleveland made it clear that his loyalty to the party would only go so far.
When Fox News moderator Bret Baier asked the candidates to raise their hands if they could not promise to support the eventual nominee -- or not run an independent campaign if they lost the primary -- Trump, standing center stage, quickly lifted his.
After a labored explanation, Trump gave a weirdly qualified assurance -- one that, in retrospect, he actually seems keen to break.
"If I am the nominee," Trump said, "I will pledge I will not run as an independent."
September 3, 2015 -- Unity! Trump signs the pledge
Four weeks later, as Trump's lead in the early polls expanded and party officials grew anxious, Republican National Committee Chairman Reince Priebus visited with the candidate in New York. At the end of their private meeting, Trump emerged with a new message.
"I have signed the pledge," he told reporters at Trump Tower, papers in hand. "So I will be totally pledging my allegiance to the Republican Party and to the conservative principles for which it stands."
In return for his signature, Trump said, the party had offered him reassurance he would be "treated fairly" as the primary contest unfolded.
December 9, 2015 -- About that pledge ...
To say that Trump moved the goalposts would be inaccurate. Their initial position, beyond the vague promises of fairness, had never been truly established.
During an interview at his offices in New York, Trump again refused to rule out an outside run.
"I think it's highly unlikely unless they break the pledge to me, because it's a two-way street," he told CNN's Don Lemon. "They said they would be honorable. So far, they, I can't tell you if they are, but the establishment is not exactly being very good to me."
The first votes were still nearly two months off, but Trump insisted on being treated "as the front-runner."
"If the playing field is not level, then certainly all options are open," he added. "We'll go through the primaries. We'll see what happens, and I'll make a determination."
February 26, 2016 -- The establishment moves toward Trump
The runner-up to Ted Cruz in Iowa, Trump won the next three GOP primary contests. Then, days after his romp in Nevada, a major endorsement arrived on his doorstep.
New Jersey Gov. Chris Christie, a one-time favorite who had dropped out weeks earlier after a disappointing finish in New Hampshire, joined Trump in Texas to give his backing ahead of Super Tuesday.
"I will lend my support between now and November in any way for Donald," Christie told surprised reporters before a rally in Texas.
"Generally speaking, I'm not big on endorsements," Trump would say. But this one, he added, "This was an endorsement that really meant a lot."
With Christie on board, Trump seemed to be making inroads with the mostly elusive party establishment. But as Trump continued to rack up the wins -- he took seven states on Super Tuesday to Cruz's three -- whispers about the potential for a convention challenge grew louder.
March 29, 2016 -- Rip up the pledge!
Trump, Cruz and Ohio Gov. John Kasich all formally abandoned the pledge during a CNN town hall in late March, as the field narrowed and the attacks turned increasingly personal.
"I'm not in the habit of supporting someone who attacks my wife and my family," Cruz said, making reference to a nasty tweet Trump had sent days earlier. "I think nominating Donald Trump would be an absolute trainwreck," he added, "I think it would hand the general election to Hillary Clinton."
Trump, meanwhile, was focused on the RNC, protesting again that he had been "treated very unfairly" by the party.
Asked by CNN's Anderson Cooper if he pledged to support the eventual nominee without reservation, Trump said simply: "No, I don't anymore."
May 4-5, 2016 -- General election arrives, but endorsements do not
After overwhelming Cruz and Kasich in the Indiana primary on May 3, Trump emerged as the GOP's presumptive nominee. And with that, the pressure was on high-ranking elected officials, many of whom had previously demurred citing the ongoing competition, to state their allegiances.
New Hampshire Sen. Kelly Ayotte, on May 4, was among the first to employ some rhetorical jujitsu, as her own campaign said she planned to support the nominee, but not formally endorse him. Others, like former Texas Gov. Rick Perry, an early (and harsh) Trump critic, did an about-face and even suggested he would be open to a vice presidential nomination.
But it was House Speaker Paul Ryan's response that underlined just how unsure the relationship between Trump and party leaders remained.
"I'm just not ready to (support Trump) at this point. I'm not there right now," the speaker said in an interview with CNN's Jake Tapper, adding that he hoped to find common ground and "be a part of this unifying process."
Trump was not impressed.
"I am not ready to support Speaker Ryan's agenda," he shot back in a statement. "Perhaps in the future we can work together and come to an agreement about what is best for the American people. They have been treated so badly for so long that it is about time for politicians to put them first!"
By the next day, the two sides had scheduled a sit-down for the following week on Capitol Hill.
May 12, 2016 -- Detente!
The makings of a fragile alliance seemed to be in the works after a meeting that was treated like a summit between the heads of warring states.
When it was over, Trump and Ryan even put out a joint statement pointing toward progress and a more decorous future.
"While we were honest about our few differences, we recognize that there are also many important areas of common ground," they said. "We will be having additional discussions, but remain confident there's a great opportunity to unify our party and win this fall, and we are totally committed to working together to achieve that goal."
Ryan did not endorse the presumptive nominee, but conceded that his primary run had been "kind of unparalleled."
Trump tweeted his delight all the same, saying, "Great day in D.C. with @SpeakerRyan and Republican leadership. Things working out really well!"
"I don't mind going through a little bit of a slow process," he told Sean Hannity on Fox News. "We're getting there."
Priebus, a close ally of Ryan's who helped broker the meeting, called it "a good first step toward unifying our party" during a subsequent interview with CNN's Dana Bash.
By June 2, Ryan had come all the way around. In his hometown Janesville Gazette, the Wisconsinite wrote that he finally felt "confident (Trump) would help us turn the ideas in this agenda into laws to help improve people's lives. That's why I'll be voting for him this fall."
With the Cleveland convention nearing, Trump had finally secured the backing of the highest-ranking Republican in the land.
July 18-21, 2016 -- Cold shoulders, a clash in Cleveland
Trump had Ryan nominally in his corner, but the quadrennial convention was beset by high-profile no-shows. Four of the party's last five presidential nominees failed to turn up, along with a number of big name officials, including Ayotte, Sen. John McCain and the host state's governor, John Kasich.
Ohio Sen. Rob Portman also steered clear of the convention stage, opting not to give a speech.
Asked by a reporter if he planned on attending, Arizona Sen. Jeff Flake, one of Trump's most consistent detractors, said, "No. I've got to mow my lawn."
One former rival who did show up in Cleveland? Ted Cruz.
But the Texas senator had a trick up his sleeve. Cruz refused to endorse Trump during his address, telling stunned and angry delegates to "vote your conscience."
It was a shocking round of staged defiance. The next morning, Cruz made his purpose clear, telling his state delegation, "I am not in the habit of supporting people who attack my wife and attack my father."
Trump initially responded with calm, but in a press conference following the convention, revived an old, odd and discredited charge that Cruz's father had in some way been in cahoots with JFK assassin Lee Harvey Oswald.
August 1-5, 2016 -- Back-and-forth with Paul Ryan
His poll numbers plummeting after a disastrous week spent attacking the parents of a slain war hero, Trump lashed out at Ryan in early August.
On the first day of the month, he tweeted praise for the speaker's primary challenger, Paul Nehlen. A day later, Trump in an interview with The Washington Post refused to endorse Ryan, turning his May words against him, saying, "I'm not quite there yet."
But after another painful news cycle littered with ugly poll numbers, Trump backed down and served up the endorsements he had so pointedly withheld.
At a rally in Green Bay, Wisconsin, he announced his formal backing for Ryan, McCain and Ayotte.
Trump would dismiss campaign chairman Paul Manafort soon thereafter, replacing him with Breitbart boss Steve Bannon and Kellyanne Conway, a longtime GOP pollster who had been working for the campaign. While Bannon's entry raised some eyebrows, Conway's elevation signaled to many that Trump might be prepared to rein in his rhetoric.
September 23, 2016 -- Cruz makes peace before the first debate
A calamitous August gave way to a resurgent September, as Trump closed in on Clinton after a few weeks of measured campaigning.
Then, just days out from the first debate, a shocker. Ted Cruz, the primary rival who sought to humiliate him on national television, came out in support of the revived Trump.
"After many months of careful consideration, of prayer and searching my own conscience, I have decided that on Election Day, I will vote for the Republican nominee, Donald Trump," he wrote in a Facebook post.
Trump received Cruz's kind words with some of his own, saying of his former opponent, "We have fought the battle and he was a tough and brilliant opponent. I look forward to working with him for many years to come in order to make America great again."
October 7-10, 2016 -- The tape hits, and breaks the coalition
A little after 4 p.m. last Friday, a video, obtained and published by The Washington Post, put a hammer to the Republicans' fragile coalition.
In the tape, Trump can be heard musing about sexual assault and engaging in otherwise graphic conversation about a number of women. Within hours of its hitting the airwaves, Trump's GOP backers began to flee.
Utah's Jason Chaffetz became the first sitting Republican congressman to publicly withdraw his support. Ayotte and McCain soon did the same. Establishment figures like former Secretary of State Condoleezza Rice called on Trump to withdraw from the race. Others said they would simply refuse to support or defend the nominee going forward.
But in perhaps the most stinging response, Ryan, who said he was "sickened" by the contents of the 2005 tape, told Trump to stay away from a GOP event in Wisconsin where they had been scheduled to share a stage. Vice presidential nominee Mike Pence was initially announced as Trump's stand-in, but that was scuppered, too.
By Monday, Ryan went a step further, telling GOP House members he would no longer vouch for Trump or defend him, and instead, per his spokeswoman, "spend the next month focused entirely on protecting our congressional majorities."
October 11 -- It all falls apart
Ryan stopped short of revoking his endorsement of Trump, but the message was clear: the long dance had come to a screeching halt.
Trump responded with a primal scream.
Over the course of about five hours, beginning early Tuesday morning, the Republican presidential nominee launched a volley of angry tweets targeting Ryan, John McCain and "disloyal R's" from around the country.
"Our very weak and ineffective leader, Paul Ryan, had a bad conference call where his members went wild at his disloyalty," Trump wrote after grumbling that he had not been credited with having won his most recent debate against Clinton by a "landslide."
"It is so nice," he continued in another tweet, "that the shackles have been taken off me and I can now fight for America the way I want to."
As his subsequent posts would confirm, Trump's desired approach meant taking on both Republicans, like McCain, and Democrats -- the latter he described as being more naturally loyal than members of his own party.
"Disloyal R's are far more difficult than Crooked Hillary," he said. "They come at you from all sides. They don't know how to win - I will teach them!"
With less than a month to go, class is in session.