"This has been an incredible evening," Donald Trump told the crowd in Phoenix as he neared the end of his long-awaited immigration speech Wednesday night. "We're going to remember this evening."

He's right. But not for the reason he thinks.

Trump's speech capped a remarkably frenetic — and manic — day on the campaign trail for the Republican candidate.

He had jetted to Mexico earlier Wednesday to meet with that country's president, an appearance that had, generally speaking, won him plaudits for his seriousness and evenness of tone. Talk of the "new" Trump — led by new campaign manager Kellyanne Conway — was everywhere.

But when Trump stepped to the podium in Phoenix — just after 9:30 p.m. Eastern — all of that talk of a tonal shift disappeared. In the single most important speech of his presidential campaign — and with the eyes of the political world on him — Trump delivered an angry affirmation of the message that won him the Republican nomination: We are going to build a wall along our Southern border, and Mexico is going to pay for it. He also repeatedly highlighted the criminal acts done by those in the country illegally and insisted it would never happen if he was elected president.

The 10-point plan Trump outlined for dealing with the country's immigration problems was entirely overshadowed by the snarling and sarcastic way in which he delivered the speech. This was Trump in the heat of battle, surrounded on all sides by doubters and haters and losers — lashing out at all of them by basking in the adulation of his core of supporters.

The day and, in particular, Trump's speech serve as a stark reminder that there is no "new" Trump. There is no pivot, no new leaf, no 2.0. Trump, at age 70 and coming off one of the most successful and surprising primary campaigns in political history, is not going to change in any meaningful way. He can change his campaign leadership — as he has now done twice. His surrogates — led by Conway — can insist that the "real" Trump is now starting to come out. But, ultimately, the candidate needs to want to — or be able to — change. And it has been clear to anyone paying attention to this campaign that Trump isn't all that interested in doing things differently.

Sure, Trump is now reading off teleprompters at rallies. (He did so Wednesday night.) And, yes, his visit with Mexican President Enrique Peña Nieto was surprisingly statesmanlike. But these are moments. And they simply aren't sustained. At root, Trump is an entertainer, a showman. He feeds off crowds and how they react to him. And when he got up in front of that Phoenix crowd Wednesday night, he gave them exactly what they wanted: Chunk after chunk of rhetorical red meat that they cheered lustily for.

The problem, of course, is that there simply aren't enough voters in Trump's base of support to elect him president. (Don't believe me? Look at any swing state or national poll.) His only possible path to victory is to grow the number of people — particularly suburban whites and Hispanics — willing to vote for him. His immigration speech will do the opposite. No one outside Trump's base will respond well to a speech that came across — for all of Trump's policy proposals — as an angry rant against the other.

So, yes, we will remember Aug. 31 and Trump's immigration speech — just as he promised the crowd. But it will be remembered primarily for killing off any notion that there is a "new" Trump waiting to be unveiled for the stretch run of the 2016 campaign. There just isn't.