Stephen Bannon (Danny Moloshok/Invision/AP, File)

On Sunday, the Trump transition team announced that Republican National Committee chairman Reince Priebus would be White House chief of staff -- but the bigger news may have been the simultaneous announcement that Stephen Bannon would serve as chief strategist and senior counselor to the president. At least, that's how the Trump team seemed to frame it: Bannon got top billing throughout the announcement,  a clear signal of the influence he's likely to hold in the White House as right-hand man to President Trump.

Bannon, like his boss, has long been a controversial figure, and a vocal critic of the GOP establishment. When Donald Trump brought him on board in August, we took a look at the message his hire sent about what campaign Trump was likely to run -- and did.

Donald Trump has assured us many times in recent days that he isn't going to change his approach to the 2016 election. "I don’t want to change," he told WKBT-TV in Wisconsin on Tuesday. "Everyone talks about, ‘Oh, well you’re going to pivot.’ I don’t want to pivot."

And if there's anything that could symbolize that resolve, it's his decision to bring the head of Breitbart News on board as campaign CEO.

The hire of Breitbart's executive chairman, Steve Bannon, and the elevation of pollster Kellyanne Conway to campaign manager effectively diminished the role of the campaign's chairman, Paul Manafort. Manafort had been in charge since Trump fired then-campaign manager Corey Lewandowski, but ran into a series of controversies over his past work and ties to the Russian government.

In Bannon, Trump brought in the head of the most unapologetically pro-Trump conservative media outlet in the country. Basically every time Trump has run into controversy, Breitbart has found a way to defend it. The conservative outlet has morphed into more of a virulently anti-establishment, pro-Trump news outlet than anything else. Critics have taken to calling it "Trumpbart" and the "Trump propaganda arm" (despite the fact that its late founder, Andrew Breitbart, was no Trump fan).

Republican presidential nominee Donald Trump is overhauling his struggling campaign amid sliding poll numbers. (Reuters)

Even when one of its own reporters said Lewandowski had grabbed her at a campaign event, the campaign denied it — and Breitbart tried to prove that the campaign was right and its own reporter was wrong. Video evidence later showed the campaign was wrong and Lewandowski did grab the reporter, Michelle Fields.

While Bannon isn't a journalist for Breitbart, his own politics permeate the website and line up nearly perfectly with the candidate whose campaign he will oversee. He has worked for Goldman Sachs, but that was a quarter-century ago. And over the last decade-plus, he's crafted an reputation as an edgy outsider fond of promoting the tea party and sticking it to the establishment.

After leaving Goldman in 1990, Bannon started an investment bank geared toward media companies. He later negotiated the sale of Castle Rock Entertainment to Ted Turner and executive produced an Anthony Hopkins movie. After 9/11, he ventured into making his own films about Republican icons, starting with Ronald Reagan. Later, he would oversee a film on Sarah Palin and one on the tea party movement.

As Bloomberg's Joshua Green reported in a profile of Bannon last year, there began his alliance with Andrew Breitbart.

“Our vision — Andrew's vision — was always to build a global, center-right, populist, anti-establishment news site," Bannon said.

Green also reported that Andrew Breitbart had "described Bannon, with sincere admiration, as the Leni Riefenstahl of the Tea Party movement."

And therein lies the problem for a Republican establishment that would like Trump to clean up his act. For non-students of history, Riefenstahl was a filmmaker and Nazi propagandist. The Post's Robert Costa reports that Bannon has encouraged Trump to run as "an unabashed nationalist" — the kind of direction that will give the establishment GOP heartburn.

Manafort was a controversial figure, but he was at least one that clearly tried to get Trump to change his failing approach to the 2016 campaign.

Breitbart has seen almost no fault with anything Trump has done this campaign. Now, it's helping to steer the ship.