US President Donald Trump has picked Robert C O'Brien, who is now serving as the state department's chief hostage negotiator, as his fourth National Security Adviser.
O'Brien is now the State Department's special presidential envoy for hostage affairs.
'I informed John Bolton last night that his services are no longer needed at the White House, ' Trump tweeted last Tuesday.
All the North Koreans and Iranians want to do is negotiate for relief from sanctions to support their economies, said Bolton, who was speaking before guests invited by the Gatestone Institute, a conservative think tank. Trump later wielded that battle as a cudgel in opposition to political opponents George W. Bush and John Bolton, who was lately ousted as his nationwide safety adviser.
He comes into the new job with backing from Secretary of State Mike Pompeo and senior Republicans in Congress.
O'Brien's appointment was backed by Pompeo, according to reports, in a sign of the secretary of state's growing stature on national security issues, making him a towering first among the equals, who would include the secretary of defense Mark Esper and Central Intelligence Agency director Gina Haspel. "Nonetheless I maintain Vietnam would had been a loyal contrivance for us to preserve out of".
"In the face of rising challenges around the world, it is time to return to a national security policy based on "peace through strength", he wrote.
O'Brien also has criticized isolationist policies, potentially putting him at odds with Trump's promises to withdraw US troops from overseas and force American allies to pay more for USA military support.
While at the United Nations, he worked with Mr Bolton, who was then the ambassador.
They relayed that the ex-national security adviser also said the president's decision to invite leaders of the Taliban to Camp David the weekend before the anniversary of 9/11 sent a "terrible signal" and was "disrespectful" to the victims of the terrorist attack because the jihadist group harbored al-Qaeda.
O'Brien is an attorney from Los Angeles who has served as a foreign policy adviser to several Republican presidential campaigns, handled a number of high-profile legal cases and previously served in several State Department positions, including as an alternative representative to the U.N. General Assembly in 2005. He was a major in the U.S. Army Reserve. O' Brien has a law degree from the University of California, Berkeley, and co-founded a law firm in Los Angeles focused on litigation and global arbitration issues.
Moments before naming Mr O'Brien as his new advisor, Mr Trump announced he was ordering "substantially" increased sanctions against Iran, which is already buckling under United States economic pressure.