This post has been updated.

Donald Trump’s tipping point came on Saturday.

“It was only a matter of time before Donald Trump crossed the kind of line he did on Saturday, when he questioned the heroism of Sen. John McCain, a Vietnam War POW,” Dan Balz writes in The Washington Post on Monday. “The question now is whether Candidate Trump is immune from the laws of political gravity or soon will be isolated and regarded as an object of scorn or curiosity rather than of presidential seriousness.”

Balz adds: “Many Republicans said Sunday that they think his attack on McCain (R-Ariz.) marks a turning point for Trump the politician.”

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Here’s a great graphical representation from our partners at Zignal Labs of what a difference one day can make in presidential politics.

This is the word cloud of Trump-related mentions on Friday:

An analysis shows that the conversation about Trump was actually more positive than negative Friday:

But, by the end of the day Saturday, there was a 15-point swing in sentiment as Twitter turned on Trump:

And this word cloud shows the extent to which the McCain comments totally overshadowed everything else:

In an op-ed in Monday’s USA Today, Trump defended his attacks on McCain for being captured and held as a prisoner of war in Vietnam for five-and-a-half years

No, not at all, he replied on Sunday when asked on ABC if he owes an apology to the Arizona senator and recipient of the Silver Star, the military’s third-highest award for valor. Speaking to Martha Raddatz, he repeatedly accused McCain — who still bears the physical scars from the torture he was subjected to while imprisoned  — of having “done nothing” for veterans.

McCain appeared on MSNBC’s “Morning Joe” early Monday to respond to Trump’s comments. Asked if Trump owes him an apology, McCain said no.

“But I think he may owe an apology to the families of those who have sacrificed in conflict,” the Arizona Republican told MSNBC. “I’m in the arena, as [Teddy Roosevelt] used to say.”

McCain — who said he’s “not a hero” — also joked about using the term “crazies” to refer to Republican voters who are responding well to Trump’s campaign.

“Listen, you know my state is a very dynamic and divisive state, and we’ve got lots of arguments and lots of debates going on,” he said. “I have hundreds of town hall meetings all over Arizona, and I’m called crazy by the people that come there. I thought it was a term of endearment.”