President Donald Trump has appointed John Bolton, the former US envoy to the UN, as his national security adviser, politically reanimating a strident Bush administration neo-conservative.
The decision comes as a surprise, not least because Mr Trump was reported to have decided against naming Mr Bolton secretary of state last year as he disliked his walrus moustache.
Mr Bolton’s new role will prove controversial since he remains an unapologetic cheerleader of the 2003 Iraq war, which the US president himself once lambasted as “a big mistake”.
Known for that bushy facial hair, curmudgeonly manner and tousled appearance, Mr Bolton is praised by conservative admirers as a straight-talking foreign policy hawk.
But the Republican was also once memorably branded by a cable television host as “a massive neocon on steroids”.
Kentucky Republican Senator Rand Paul described Mr Bolton last year in an op-ed as “hell-bent on repeating virtually every foreign policy mistake the US has made in the last 15 years”.
A Baltimore fireman’s son, Mr Bolton has been a staunch conservative from his boyhood.
At the age of 15 he took time off school to campaign for Barry Goldwater in the 1964 presidential campaign.
At Yale University, where he studied law, he recalled in his memoir feeling like a “space alien” among the campus anti-Vietnam war activists.
Bill and Hillary Clinton were among his classmates, but he said he “didn’t run in their circles”.
Mr Bolton went on to serve in the administrations of Ronald Reagan, George HW Bush and George W Bush.
He ruffled feathers in the second Bush administration where he initially worked as US Department of State under-secretary for arms control.
Mr Bolton was accused of trying to force out two intelligence analysts who disagreed with him and of seeking to undermine his boss, Colin Powell.
He also helped build the case that Saddam Hussein possessed weapons of mass destruction, which turned out to be wrong.
But Mr Bolton was praised for his work establishing the Proliferation Security Initiative, an international agreement to prohibit fissile material shipments.
Nevertheless, President Bush dismayed diplomats when he named Mr Bolton as US ambassador to the United Nations.
More than 100 former US envoys signed a letter urging senators to reject the nomination.
This was, after all, the man who had once said there was “no such thing” as the UN and called the US the world’s “only real power”.
Mr Bolton had also previously declared that if the 38-storey UN building “lost 10 storeys today, it wouldn’t make a bit of difference”.
President Bush had to use a recess appointment to crowbar Mr Bolton into the job in 2005 after Senate Democrats, and even a few Republicans, blocked the move.
Democrats ultimately refused to confirm Mr Bolton and he had to step down when his appointment expired in January 2007.
Diplomats at the UN privately criticised his style as abrasive.
Even the state department was not spared the ire of Mr Bolton, who is known for his scorn of dovish multilateral institutions.
He once derided careerists at the US foreign ministry as having been “schooled in accommodation and compromise with foreigners, rather than aggressive advocacy of US interests”.
Mr Bolton, a senior fellow at the American Enterprise Institute, does not appear to have modified his views since his last spell in government.
As he briefly weighed his own run for the US presidency in 2016, he maintained the American-led invasion of Iraq had been “correct”.
He also called in a New York Times op-ed for Iran to be bombed, and pilloried President Obama’s nuclear deal with the Islamic Republic as a “diplomatic Waterloo”.
In his memoir, Surrender is Not an Option, Mr Bolton railed against the “deadening Brussels bureaucracies” of the European Union.
And in a recent op-ed for the Wall Street Journal, he set out the case for a pre-emptive strike on North Korea.
His new role at the commander-in-chief’s ear may perplex those who voted for Mr Trump because of his vow to avoid US military adventures overseas.