U.S. President Donald Trump answers questions from the press before departing the White House in Washington D.C., the United States, on March 13, 2018. U.S. President Donald Trump on Tuesday announced he was replacing Secretary of State Rex Tillerson with Mike Pompeo, chief of the Central Intelligence Agency (CIA). (Xinhua/Ting Shen)

WASHINGTON, March 13 (Xinhua) -- In the biggest cabinet shakeup ever since he assumed office in 2017, U.S. President Donald Trump on Tuesday ousted Secretary of State Rex Tillerson and announced he would be replaced by Mike Pompeo, director of the Central Intelligence Agency (CIA).

The departure of Tillerson, the second Trump cabinet member to leave, may indicate a more aggressive and unilateral U.S. foreign policy.

NEVER "TRUMP'S GUY"

The U.S. media said that the biggest reason for Tillerson's leaving was that he has never been a "Trump's guy," referring to his divergences with Trump on personality and policies.

Although his nomination as state secretary had won the recommendations from former Secretary of State Condoleezza Rice and defense chief Robert Gates, Tillerson clashed with Trump over both domestic and international issues.

After Trump made the highly controversial remarks over Charlottesville's racial violence that many said have racist implications, Tillerson stood up against him by saying that "the president speaks for himself" and "we represent the American people."

Sources were also quoted as saying that Trump was irritated by Tillerson's body language during meetings, as the latter was said to "roll his eyes or slouch" when he disagreed with the decisions of his boss.

Widening differences on foreign policies and international issues further escalated the tensions between the two.

Trump told the media that he and Pompeo are "always on the same wavelength," yet with Tillerson, they "disagreed on things."

"With Mike Pompeo, we have a similar thought process," Trump said. "I actually got on well with Rex but it was a different mindset."

Tillerson's support of Washington staying in multilateral treaties and organizations such as the Iran nuclear deal and the Paris climate accord, and his promotion of unconditional dialogue with Pyongyang, have all made him unpopular with the Trump administration and unable to get into the ultimate decision-making circle.

Even in his just-concluded trip to Africa, Tillerson was still making efforts to "clean up" Trump's derogatory comments on African nations.

LOSSES OVERSHADOW GAINS

In the eyes of some U.S. media outlets, Tillerson had some "successes" in his less than 14-month term, including the growing pressure against Pyongyang to force it to abandon the nuclear project, and the improved ties between Saudi Arabia and Iraq.

"But he is likely to go down as among the least successful secretaries of state in history, and one big reason was his poor management of his relationship with Mr. Trump," said a New York Times report.

Tillerson's sour ties with Trump have undercut the authority as secretary of state.

Representative Nancy Pelosi, the House Democratic leader, tweeted on Tuesday that "Whenever Secretary Tillerson's successor goes into meetings with foreign leaders, his credibility will be diminished as someone who could be here today and gone tomorrow."

Besides the cut of budget and personnel recruitment in the State Department, veteran diplomats also accused Tillerson of communicating insufficiently with them. Rather, he was said to rely on his top aides, "neither of whom had much experience or knowledge about many of the countries they discussed."

Trump was reportedly planning to sack Tillerson also in a bid to ensure his diplomatic team is in place before the U.S. talks with Pyongyang and negotiations on key trade deals.

INCREASING ASSERTIVENESS IN U.S. FOREIGN POLICY

Analysts said that Tillerson's leaving and being replaced by Pompeo may indicate further aggressiveness in U.S. foreign policy and the U.S. trade stance.

Brookings Institution Senior Fellow Darrell West told Xinhua that Tillerson, with a "softer" approach to international affairs than Trump, "believed in diplomacy and wanted to engage allies in U.S. activities."

"That ran contrary to Trump's 'Lone Ranger' approach of relying upon himself for major initiatives," he added, noting that the White House "likely will take a tougher stance on foreign policy because there will be fewer impediments to Trump being Trump."

Dan Mahaffee, senior vice president and director of policy at the Center for the Study of the Presidency and Congress, also told Xinhua that the sacking of Tillerson was a sign for Trump to "double down on the idea of letting 'Trump be Trump' and removing a voice of moderation -- even if controversial in his departmental management."

"The president will have greater leeway to follow his own instincts on foreign policy and he will be less restrained in taking actions," West said.

He predicted that Pompeo may take a tougher line on the talks with Pyongyang. "Trump probably will be more impulsive and more prone to rattle cages around the world."

Mahaffee added that the dismissal "further sidelines the State Department and traditional diplomatic efforts as the effort is largely being driven by Trump himself" in the U.S. further engagement with Pyongyang.

Also in terms of the Iran nuclear deal, which Trump lambasted on Tuesday as "terrible," the U.S. stance may get tougher under Pompeo.

"That is consistent with Trump's overall perspective and geo-political concerns regarding Iran's role ... There likely will be close attention to Iran with the new leadership," West said.

Mahaffee also said Tillerson's leaving may create "a complex impact" on the U.S. trade relations with other nations.

"Tillerson had been a voice for avoiding a trade war ... (the Tillerson firing) makes it much easier to have an 'America First' approach in the truest sense of what was heard on the campaign trail, as Trump is removing a moderate, pragmatic voice from his cabinet," said Mahaffee.

Max Boot, a senior fellow for national security studies at the Council on Foreign Relations, also voiced concerns over the future U.S. foreign policy.

"Does that mean that Trump is now likely to scrap the Iranian nuclear deal at the same time that he is meeting with Kim to discuss the denuclearization of North Korea (the Democratic People's Republic of Korea)?" he said.

"This is a schizophrenic approach that is likely to lead to failed talks with North Korea, which could in turn lead to a renewed push within the administration to launch Korean War II. For all his faults, Tillerson knew that a war with a nuclear-armed state was a bad idea. Does Pompeo?"