After the disappointment of the 2012 elections, the Republican National Committee commissioned an “autopsy” to examine the party’s flaws, and ways to move forward. One of the key recommendations: the party must “must embrace and champion comprehensive immigration reform.”

There was virtually no discussion in the document of that highly controversial claim, which was made almost in passing, as if the party would swiftly reach consensus on immigration reform and pass it without much debate.

That sentiment reflected the prevailing orthodoxy among conservative pundits, as well. On November 8, 2012 — four years to the day before Donald Trump’s amazing victory — the estimable Charles Krauthammer wrote:

Hispanics … should be a natural Republican constituency: striving immigrant community, religious, Catholic, family-oriented and socially conservative (on abortion, for example). The principal reason they go Democratic is the issue of illegal immigrants. In securing the Republican nomination, Mitt Romney made the strategic error of (unnecessarily) going to the right of Rick Perry. Romney could never successfully tack back. For the party in general, however, the problem is hardly structural. It requires but a single policy change: Border fence plus amnesty. Yes, amnesty. Use the word. Shock and awe — full legal normalization (just short of citizenship) in return for full border enforcement.

Amnesty — as soon as possible. That was the conventional wisdom in Washington. But conservatives surprised the GOP establishment by resisting amnesty, by insisting on debating the fundamental issue of who is to become an American, and how.

And President-elect Donald Trump shocked the political world by riding to the presidency on opposition to amnesty.

What the Republican establishment underestimated was how deeply Americans — including key Democratic constituencies, and even legal immigrants — resented amnesty. For some, it was a matter of economic competition. For others, it was a matter of the rule of law. And for others, it was a matter of cultural coherence.

Regardless, Donald Trump reached voters that the GOP had long forgotten by promising to “build a wall” with a “big, beautiful door.”

It was not a call to xenophobia. It was a claim that the diversity that Americans have always cherished — e pluribus unum — rested on the foundations of secure borders, and law enforcement, and fairness.

If we don’t have a border, Trump argued, we don’t have a country.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. His new book, See No Evil: 19 Hard Truths the Left Can’t Handle, is available from Regnery through Amazon. Follow him on Twitter at @joelpollak.