Barack Obama's young chief speechwriter Ben Rhodes became so adept at channelling his boss' soaring rhetoric and political world view that he was often described as having achieved a "mind meld" with the president.
By the time Obama left office, Rhodes was considered brilliant in Washington circles, but some in the foreign policy establishment fretted that he might have become too influential, that he might have helped shape Obama's foreign policy as well as his words.
Today in the angry, swirling Trump administration, another young man has achieved similar stature. You might not have heard of Stephen Miller, but you have likely heard his words.
Before Miller wrote Donald Trump's bellicose address to the United Nations this week, the 32-year-old was perhaps best known as the author of Trump's dystopian inaugural address, now known simply as the "American carnage" speech.
Parting with the tradition of using the event to bind together a nation battered by the long campaign behind it, Trump opted instead to describe America as a ruined landscape driven to the very brink of absolute collapse by devious DC insiders. Leaving the ceremony afterwards former president George W. Bush was overheard observing, "That was some weird shit."
But Miller is more than a speechwriter for Trump. With the nationalist Steve Bannon bounced from the administration, Miller - a Bannon ally - remains the most steadfast champion of the "America first" message that Trump used to seal his unlikely election victory. Miller is a key architect of Trump's attempts to ban citizens from some Muslim majority nations from entry into the US.
Trump's declarations at the UN that the US "can no longer be taken advantage of or enter into a one-sided deal where the United States gets nothing in return," and that "Major portions of the world ... in fact, are going to hell," are signature Miller flourishes.
Miller grew up in a progressive Jewish Californian family before turning to deeply conservative nationalist politics while a student in a diverse Santa Monica high school. In a profile of him earlier this year Univision unearthed a letter he wrote at the time to a local publication voicing his poor view of his Hispanic classmates.
"When I entered Santa Monica High School in ninth grade, I noticed a number of students lacked basic English skills. There are usually very few, if any, Hispanic students in my honours classes, despite the large number of Hispanic students that attend our school," he wrote.
"Even so, pursuant to district policy, all announcements are written in both Spanish and English. By providing a crutch now, we are preventing Spanish speakers from standing on their own," he added. "As politically correct as this may be, it demeans the immigrant population as incompetent, and makes a mockery of the American ideal of personal accomplishment."
According to some reports Miller was originally politicised after reading the book Guns, Crime and Freedom by the firebrand NRA chief Wayne LaPierre???. Certainly LaPierre's speeches and Miller's rhetoric are similarly bleak and angry.
Later as a student at Duke University, Miller became friends with Richard Spencer, the white ethno-nationalist who is viewed as the creator of the alt-right movement. Spencer told Vanity Fair that he remembers Miller as a "ballsy" American nationalist.
On graduating Miller went to work for the Tea Party leader Michelle Bachmann and then Jeff Sessions, the then US senator who has now been made Trump's attorney-general.
He joined Trump's campaign in January 2016 as a policy adviser but made his mark by acting as Trump's warm-up act on the campaign trail. He railed against the dangers of mass immigration, the perfidy of the Clinton campaign and the need to wall off America's southern border, fleshing out the more freeform addresses that Trump dazzled his crowds with later.
Today he remains by title a senior policy adviser but, like Rhodes before him, he appears to have achieved that mind meld with his boss, helping not just to shape the words of the Trump presidency, but its deeds too.
