Taking Out Donald Trump: 5 Moments the Establishment Missed

— -- Donald Trump won overwhelmingly in last night's Super Tuesday contests, and is now the presumptive GOP nominee. An amazing situation very few people anticipated though, if eyes were wide open, it shouldn't have been shocking.

Trump isn't inevitable, but he certainly is in a very dominant position where it will be incredibly difficult for him to be taken out. It seems the only way to beat him is through a contested convention.

I have been arguing since the summer that Trump had the best odds to be in the nominee. He was the most in sync with where a large segment of the Republican voters are this year, had a better understanding of politics today for the GOP, and had a mastery of the new media environment that no other candidate had.

It is not that the media created Trump. Trump became the leading candidate primarily on his own, and understood the changing media environment and how to get maximum exposure.

The question is: Could he have been stopped by the insiders and GOP establishment who today are wringing their hands and are in full on war to try and take him out? In looking back, I note five windows of opportunity missed by Republican candidates and the GOP establishment if they had wanted to stop his momentum and, possibly, his candidacy.

Obviously, we don't know with a high degree of confidence whether it would have worked, but they were the best moments, had GOP insiders wanted a higher degree of success.

Early Spring 2015

Stronger potential GOP candidates passed up on running because they mistakenly believed Jeb Bush had built a juggernaut, raised tons of money and would be the dominant candidate. This race could have been vastly different if candidates such as Mitt Romney or others had not taken a pass on this race because they bought into the myth of money and the Bush brand. I have been saying for years, money matters very little in creating success in politics, and this year proves it isn't the most important strategic imperative.

Late Summer 2015

It became readily apparent to me, and in the polling, that Trump wasn't going away anytime soon and he was the leading candidate. Trump was beginning to build momentum and an attachment with GOP voters that, once solidified, would be harder to break. This is when the establishment and other candidates should have taken him on in a more forceful way. And try to keep that attachment from getting "sticky.”

Jeb Bush, Sen. Ted Cruz and others should have directed their large money and organization advantage at Trump in late-summer.

Summer-Early Fall 2015

Candidates neglected to see early on the importance of debates in framing themselves and Trump. Debate moments matter way more than money, TV ads, trips and ground game. They affect candidate perceptions and attachments far more than anything else. Jeb Bush, Gov. John Kasich and others should have spent more time on debate prep, and figuring out the best way to convey strength and connection with voters. In addition, after each debate, the establishment should have used this opportunity to undermine Trump as voters were trying to sort out what happened at each debate.

First Week of February 2016

In the aftermath of Trump's second-place finish in Iowa, the establishment and other candidates should have made a concerted effort to attack him while he was wounded. Trump was weakened at that point and blood had been drawn, so his opponents should have piled on in advance of the New Hampshire primary. Instead, these candidates ignored him, and took after each other. So instead of lowering Trump's margin in New Hampshire, they actually helped build it up, creating momentum for his South Carolina victory.

Debate Before N.H. Primary

Sen. Marco Rubio had momentum coming out of his surprise third-place showing in the Iowa caucuses, and was prepared to start bringing together the establishment behind him. He then, needlessly, flubbed in the debate prior to the first-in-the-nation New Hampshire primary on Feb. 9, which could have been prevented by debate prep and understanding what was about to come his way. Everything that happened at that debate was telegraphed before, but Rubio was not ready to meet the important moment.

Can Trump be stopped now going forward post Super Tuesday? Possibly, but it is more and more unlikely. The time to have slowed him was in the five moments listed above, and these opportunities were neglected out of arrogance, ignorance or whatever reason.

And, in the end, Trump's success has nothing to do with the media’s propping him up. The responsibility lies with Trump having a much better intuitive read on the GOP electorate and the modern media environment. And the blame lies with the establishment, GOP insiders and other candidates who discounted Trump's abilities, the desires of GOP voters and didn't take advantage of clear windows of opportunity.

There you have it.

Matthew Dowd is an ABC News analyst and special correspondent. Opinions expressed in this column do not necessarily reflect the views of ABC News.