Story highlights Tamar Jacoby: Trump's speech was no pivot; it offered distortions on immigration and was notable for what it left out

Jacoby: Speech focused on exaggerated threat, with little understanding of what immigration, now at 10-year-low, brings to America

She says no amount of Trump's scapegoating will make this the major problem we face as a nation

Tamar Jacoby is a registered Republican and president of ImmigrationWorks USA, a federation of small business owners in favor of immigration reform.The opinions expressed in this commentary are solely those of the author.

(CNN) So much for the Trump immigration pivot. It was intriguing while it lasted -- all 10 days. Last night, the old Trump was back.

His much anticipated immigration speech Wednesday night began with a throwaway line about his "love for the people of Mexico," and he blew a few kisses at his new best friend, President Enrique Peña Nieto of Mexico. Also uncharacteristically, Trump had done a little homework, consulting with experts and studying up on immigration law.

But most of the 73-minute speech was given over to a wild, dystopian rant: criminal aliens, foreign terrorists, runaway welfare use, immigrant-driven job loss and downward wage pressure -- an immigration system, Trump summed up, that's "worse than anybody ever realized because the media won't report on it."

That's a hard claim to counter -- by design. If you buy it, it means no known facts matter. No one else's arguments carry any weight, because others don't know what you know. And in Trump's telling a handful of appalling instances -- cases in which an unauthorized immigrant slated for deportation murdered an American citizen -- outweigh all that immigrants contribute to the United States, economically and in other ways.

The GOP candidate's Manichean vision is simple and clear. If anything, it came through more starkly in this supposedly sober, considered address than it has in over a year of unscripted stump speeches.

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