When Donald J. Trump delivers the biggest speech of his short political career Thursday night, most of the words he will say will have been crafted by a 30-year-old former staffer for Sen. Jeff Sessions (R-Ala.)

Stephen Miller, who worked for Sessions for seven years–most recently as communications director–prior to joining the Trump campaign in January. Miller first worked with Trump’s team last year when Sessions’ asked Miller to help them draft Mr. Trump’s immigration position.

A Capitol Hill insider close to Sessions’ senate office explained the significance of the Miller hiring back when it first happened.

“Anyone who has been around (Senator Sessions) these last few years knows how much the senator has relied on Stephen,” he said. “In the heat of the Gang of Eight (immigration bill) fight, Stephen was the one prepping the senator for every interview and putting out all those press releases and research that made their office the hub of information for the anti-amnesty Right. (Stephen) has been responsible for who-knows-how-many Breitbart, Yellowhammer and Drudge headlines over the years. Trump doesn’t need help getting headlines, of course. But what I am saying is Stephen is so in tune with the way regular Americans are thinking — you know, the kind of nerve Trump is touching right now. He’s the kind of guy who Trump’s going to need around him to flesh out his policies. It’s a great fit.”

That analysis has since then proven to be correct. Trump campaign manager Paul Manafor called Miller “one of the most important people in the campaign” and praised him for perfectly capturing “Trump’s voice” in his speechwriting. Trump’s campaign speeches are typically done without notes, much less a teleprompter, but the handful of major policy speeches that he has delivered were penned by Miller.

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“I remember saying a few years ago to friends that I hoped Donald Trump would run for president,” Mr. Miller told the Wall St. Journal. “The clarity with which he talked about trade and immigration, and the sense that he alone had the power to disrupt the special interests and give government back to Americans, made clear to me that he was the leader we needed.”

Miller first garnered attention in the conservative movement by vocally defending the Duke Lacrosse team against what turned out to be false rape allegations. Appearing on national television in his roles as a columnist for the Duke student newspaper and Executive Director of the Duke Conservative Union, Miller defended the rights of Duke lacrosse players against individuals leading what he described as a “witch hunt for political gain.”

He later served as press secretary to former Congresswoman Michele Bachmann (R-Minn.) and others before joining Sessions’ staff.

Miller’s introduction of Sessions at a political event in 2014 gives insight into both his affinity for the Alabama senator and the way he views the current mood of the electorate.

The one thing people crave above all else at this moment in history in the people they send to Washington is authenticity — people who are real, and in person, in private and in public the same person — people of character and integrity and dignity — people you can rely on to defend your interests and your values and to never be persuaded or influenced or manipulated by forces and interests and people who do not have the interests of America at heart.

And if there’s one person in this whole country who we all know to be that person, it is Senator Jeff Sessions. He is the most authentic and sincere and dedicated person that anyone could ever have the privilege to work for…

One of the things we’re missing from our political dialogue right now is the idea that the United States is a home. It is more than an accounting sheet. It is more than the sum of its GDP, it’s total tax collections or its total outlays. America is a family. America is the place that we love, to whom we give our loyalty and our allegiance and our devotion.

But Washington has forgotten for too long that it owes its loyalty, dedication and devotion to the citizens of this country who call it home. Washington does not serve the interests of people living overseas or corporations headquartered all across this globe, but the real flesh and blood citizens who together create this nation, this home…

And if there’s one man we can all rely on to defend the interests of that country and its people and its citizens, it’s United States Senator Jeff Sessions.

And now Miller has perhaps added Donald Trump to that list as well.