Donald Trump (Brennan Linsley/AP)

Donald Trump has said he prefers war heroes who weren't captured. He said Mexico was sending "rapists" and "criminals" to the United States. He proposed a temporary ban on Muslims entering the country. He falsely claimed that "thousands" of Muslims were celebrating in northern New Jersey on Sept. 11, 2001.  He said Fox News's Megyn Kelly was mean to him in a debate because she had blood pouring out of her "wherever."  He said he could shoot someone in the middle of Fifth Avenue and his supporters would continue to back him. He suggested that Ted Cruz's father was part of a plot to assassinate John F. Kennedy. He created a fake spokesman to tout himself.

Any of these things would have ended — or at the very least, badly hamstrung — a normal campaign. None of them had that effect on Trump. Quite the opposite.  His proposal to build a wall with Mexico sent him surging in the polls in the early days of the race. His reaction to the Paris and San Bernardino attacks — the Muslim ban — wound up being the key to a second Trump surge that effectively won him the nomination.

The up-is-down-ism of Trump's primary campaign led — and leads — many people to conclude that nothing he says or does will have any negative impact on his chances of winning the White House. Nothing hurts this guy!  He tells it like it is and people love it!

I'm less certain of that — even while acknowledging that Trump's campaign to date has succeeded by doing the exact opposite of what conventional political wisdom would suggest.

Witness the reaction to Trump's comments over the past few days regarding Gonzalo Curiel and the allegation that the judge's Mexican heritage effectively disqualifies him from offering an unbiased view of a pending case regarding Trump University.

Unlike even a few months ago when Trump was making offensive comments, the condemnation from across the spectrum of the Republican party has been both swift and biting. Newt Gingrich, widely rumored to be a member of Trump's vice presidential shortlist, called the comment "inexcusable" and described it as the "worst mistake" Trump has made in the campaign to date. House Speaker Paul Ryan, a day after he endorsed Trump, said that he "completely disagree[d] with the thinking" behind Trump's comment on Curiel. Senate Majority Leader Mitch McConnell said he "couldn't disagree more with a statement like that."  Maine Sen. Susan Collins tweeted out her disapproval Monday morning.

As of Monday afternoon, the piling-on of Trump from all corners of the GOP showed no signs of abating — and Hillary Clinton's campaign had seized on the controversy with a brutal Web video detailing all of Trump's Republican critics.

So what, you say? Lots of Republicans have called out Trump before for things he said — and it helped him! And Clinton attacking Trump is nothing but good for Trump as he tries to unite the GOP!

I'm not so sure. As I noted above, I think the number of Republicans condemning Trump and the language they are using to do it is qualitatively different than in the past. I also think Trump's circumstances have changed markedly since he made most of his most famous/infamous comments.

Trump is no longer one of a crowd of candidates running for the Republican nomination. He is the presumptive Republican nominee. He is the de facto head of the Republican party, responsible not only for himself but also for the broader brand up and down the ballot in November.  There are greater stakes now than at any other time in the past when Trump has said something controversial. He now speaks for the entire party — and doesn't seem to realize it or, more frighteningly for the GOP, doesn't care.

That new reality means that Trump's comments can't simply be dismissed by Republican leaders as "Donald being Donald." What Trump says and does now matters more. Which means that the likes of Ryan and McConnell, who are desperately trying to preserve some semblance of the party they know and love, have to be more outspoken and confrontational when Trump goes off the rails.

Then there is the fact that Trump isn't running for the Republican nomination anymore. He's running to be president of the entire United States, which means that simply carving out a bigger-than-anyone-else-can-carve piece of the GOP primary pie isn't close to enough anymore.

Consider this: Trump is likely to win the Republican primary race with somewhere in the neighborhood of 12.5 million votes. Mitt Romney got 60 million votes in 2012 while losing convincingly to President Obama.  Trump needs to massively scale upward in terms of his voter pool to have a serious chance against Clinton. And the sort of voters he needs to appeal to are not the hardcore Republicans who are already for him. They are establishment GOP types, moderates and even some Reagan Democrats. They are, by and large, also not the sort of people who will respond well to Trump's Curiel comments.

No one can dispute that Trump broke every rule in the Republican primary and won. But winning a primary and winning a general election are not even close to the same thing. (Think about it like being a star in college basketball and a star in the pros.  Some people can do both but the skill set required is not the same.)

This is a whole new ballgame for Donald Trump. He doesn't seem to understand that. Maybe the Curiel controversy will convince him that he needs to change — or at least adapt — to win. But I doubt it.