They are the six figures often seen in the background as Donald Trump is photographed carrying out presidential business. Yet they are at the forefront of much of the White House decision-making.

Since taking office, Mr Trump has put his trust in those who helped get him there, placing key campaign aides into position of real power.

He's added a senior political adviser to the National Security Council and appears to have cut out Cabinet secretaries from decision making on some of his top policies, including the immigration and refugee order that led to protests, legal challenges and temporary detention of some legal US residents.

Mr Trump has empowered a small group of advisers, some of whom have no experience in government, to tackle a broad range of issues - including national security, the immigration policy, US relations with Mexico and plans to repeal President Barack Obama's health care law.