WASHINGTON - White House chief strategist Steve Bannon has resigned from the Trump administration, a source close to Bannon tells ABC News.

The source said Bannon made the resignation effective two weeks ago, effective Aug. 14 - the one year mark of his joining the campaign.

He says he will continue to fight for the president's agenda outside the White House.

Bannon joined the Trump campaign in August 2016 as the third man to run Trump's floundering campaign - and in the process of helping lead Trump to that improbable victory became the embodiment of Trump's populist agenda - following him to the White House as his chief political strategist, where he would cement his reputation as fearless and critically influential adviser determined to stick to his motto until it finally got him killed.

Before joining forces with Trump he was an investment banker at Goldman Sachs, a movie producer, and a video game investor -- but without doubt was best remembered for running Breitbart News, an inflammatory alt-right news site that produced headlines under his leadership so controversial his detractors were able to fuel suspicion that Trump had essentially hired a white supremacist.

Bannon has clashed with virtually every top official in the White House. Atop his list of in-house detractors are senior adviser Jared Kushner, national security adviser Lt. Gen. H.R. McMaster and the new chief of staff, Gen. John Kelly.

One of McMaster's first moves was to remove Bannon from his seat at the table during meetings of the National Security Council, a move that angered Bannon. And his appointment there as a chief political strategist was hugely controversial when it was first announced via executive order at the start of the administration.

Over the weekend McMaster refused to say whether he would continue to work with Bannon or not, even after being pressed repeatedly on Meet the Press.

And of course President Trump himself had grown increasingly frustrated with Bannon, according to one senior white house official.

Yesterday left little doubt that Bannon's interview with The American Prospect was deeply annoying to Trump's cabinet. Visibly frustrated, both Secretary's Tillerson and Mattis were both forced to respond to Bannon's highly contradictory comment that there was no military solution in North Korea... "forget it... they got us" he told the magazine. That came just days after the President threated "fire and fury" like the world had never, and had surprisingly seemed to win the war of words with Kim Jong Un, who tampered down his rhetoric faced with Trump's bluster.

It's certain that interview also irritated Trump.

We know too that many people had Trump ear on this issue, Anthony Scaramucci and Rupert Murdoch both have privately urged him to fire Bannon in recent weeks.

Then again there are pitfalls to Bannon's departure at this moment in time. Some are certain to speculate this move will be seen as an admission from the White House that a) Bannon's influence, particularly as a member of the alt-right, is toxic and b) Trump botched his response to Charlottesville, a belief that many in his party have settled on.

Also remember that in that wild press conference on Tuesday Trump denied that he spoke to Bannon before delivering those controversial "on many sides" remarks over the weekend.
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