WASHINGTON (WASHINGTON POST) - Secretary of State Rex Tillerson, who White House officials said is likely to be replaced within weeks, was supposed to be the camera-ready face of a tougher, more disciplined US foreign policy under President Donald Trump.

Instead, he has become a symbol of dysfunction and tension, and the subject of months of rumours about his declining stock in a chaotic administration. If he does head back to his Texas ranch soon, Tillerson will leave without banner diplomatic achievements and with little to show for his signature effort at downsizing and streamlining the State Department.

He would not be greatly missed by the rank and file at State, several current and former officials said privately, although his supporters suggested that he has far stronger credentials than his most likely replacement, CIA director Mike Pompeo.

"I really have no way of rating Pompeo," Senator Bob Corker said Thursday as reporters asked him about reports that Tillerson would soon be fired and replaced by Pompeo, a hawkish former congressman who was a leading critic of the international nuclear deal with Iran. "I could barely pick Pompeo out of a lineup," Corker added.

He said he had spoken at length with Tillerson on Thursday and did not believe he was about to be sacked.

Representative Adam Smith, the top Democrat on the House Armed Services Committee, told C-SPAN on Thursday that he is "not optimistic that the State Department's going to get better under Secretary Pompeo".

"I've served with Congressman Pompeo. I'm not sure he's a significant upgrade from Secretary Tillerson," Smith said. "At least Secretary Tillerson, when he worked for ExxonMobil, was very global. He knew he had to work with other countries."

Tillerson went about his day as usual, including two routine meetings at the White House, department spokesman Heather Nauert said. White House Chief of Staff John Kelly called Tillerson's chief of staff, Margaret Peterlin, to say the "rumours are not true", according to Nauert. She said Tillerson "brushed this off today" because he's lived through rumours of his imminent departure before.

The State Department announced Thursday that Tillerson will travel to Europe next week for meetings with NATO and European Union officials. "He remains, as I have been told, committed to doing this job," Nauert said. "He does serve at the pleasure of the President."

Asked about Tillerson on Thursday, Trump said only, "He's here. Rex is here." Tillerson came to office in February with no experience as a diplomat but with four decades under his belt conducting oil negotiations around the world during his career with Exxon.

Ronald Neumann, president of the American Academy of Diplomacy, said Tillerson's record is mixed. "To be fair to Tillerson, people ought to stop merging his performance as a diplomat and his performance as a manager," he said. "As a diplomat, he's not done all that badly." Neumann credited Tillerson with applying classic diplomacy to dealing with North Korea, and helping persuade Trump to sign two certifications of Iran's compliance with the nuclear accord.

James Jeffrey, a former US ambassador who keeps in touch with Tillerson since he came to Washington, said Tillerson deserves credit for doing "damage control" by acting as a moderating influence on some of Trump's positions and helping to broker cease-fires in Syria that are holding in some parts of the country. "US foreign policy, a year after the President came into office, looks a helluva lot like the foreign policy of Barack Obama," Jeffrey said, crediting the President's national security team with mitigating some of Trump's more dramatic foreign policy pledges.

Still, Tillerson has lost most of the policy disagreements he faced behind closed doors, including whether to withdraw the United States from the Paris climate accord and, ultimately, whether to continue certifying Iranian compliance with the nuclear deal. Trump declined to do so in October, and the deal's future is now in limbo.

The risk from North Korea, Tillerson's most high-profile diplomatic challenge, appears to be worse than when the administration took office - Pyongyang has now tested an intercontinental ballistic missile that appears capable of reaching the continental United States, and its leader, Kim Jong Un, has refused to come to engage in talks that Tillerson has offered.

Nancy McEldowney, former director of the Foreign Service Institute, said she considers Tillerson an honourable man who has tried to do a job for which he is not a good fit. "He's uncomfortable with the give-and-take of policy deliberations," she said. "He's very reticent at public advocacy. Everyone who meets him believes he's an honourable and honest man. But he's ill-suited for the position."

Much of the criticism of Tillerson has revolved around how he has managed planned budget cuts and an 8 per cent staff reduction that the White House has ordered him to make. The State Department has offered buyouts to more than 600 employees in addition to a hiring freeze, measures that will eventually lead to 2,000 fewer employees.

Already, dozens of senior diplomats with decades of experience have resigned or taken early retirement. Foreign Service officers posted overseas scramble to avoid returning to Foggy Bottom, increasing the competition for the few foreign postings that come open.

All of this comes amid a reorganisation that Tillerson, who oversaw three mergers while at Exxon, considers the most important thing he will accomplish at the State Department. But after months of questionnaires and interviews and workshops to gather employee input, Tillerson has yet to outline a timetable or a vision other than promising efficiency and job satisfaction.

Neuman said the reorganisation has dragged on, contributing to low morale and a sense of drift. Lawmakers who sit on committees with oversight of State Department operations have written Tillerson numerous letters appealing for more consultation. "There's no reason the reorganisation needed to be going on for months and months," Neumann said. "It's caused enormous pain. We're hemorrhaging our most senior diplomats."

After 10 months on the seventh floor, where his office is located along with those of a small group of senior advisers, Tillerson has not won the allegiance of most members of staff. He is viewed by many as a remote presence, at best.

Only a handful of diplomats from regional bureaus have had regular facetime with him, while most have no access to either Tillerson or his senior advisers, Jeffrey said. The faltering reorganisation has cost Tillerson support, Jeffrey added, from both the staff and the White House, which never asked for it in the first place.

Defense Secretary Jim Mattis, Tillerson's closest ally in the administration, told reporters who asked about the rumours of Tillerson's departure, "There's nothing to it." But few within the State Department or in the foreign policy community expect him to stay a full four years.

Whenever he leaves, McEldowney said, Tillerson will walk out of an agency that's smaller and weaker than when he arrived. "It's been starved for resources, human and fiscal," McEldowney said. "The workforce is dispirited. Relations with key allies are severely strained. Our standing in the world has plummeted in almost every country. Our reputation as a promoter of democracy and an exporter of stability is gone."