Tillerson faced a grilling from Republican Sen. Marco Rubio, who represents a vital vote in the narrowly-split Senate and could have outsize influence on whether Donald Trump's pick to be the top US diplomat is confirmed.
The Florida senator put Tillerson on the spot on human rights violations in Russia and the Philippines especially, and later told reporters he was undecided whether to back him after hours of Senate confirmation hearings.
The tug of war between advocacy for human rights and strategic interests has been a recurring theme across administrations since Jimmy Carter's presidency. Tillerson's answers in the hearing, his own past dealings with autocratic leaders as head of ExxonMobil and Trump's apparent admiration for strong leaders like Russian President Vladimir Putin, have some human rights advocates and lawmakers concerned that the incoming Trump administration will pay little heed to human rights as it frames its foreign policy approaches and could fall further off the American agenda.
In 2005, in his second inaugural address, President George W. Bush proposed a freedom agenda to push democratic change around the world but critics later said he did not live up to those heady vows. The outgoing Obama administration has also been criticized for not giving human rights a more prominent role in its dealings with US adversaries like Iran, Cuba and China. Now, human rights advocacy groups are registering increasing concern about the incoming Trump administration's position on the issue.
Rubio, who lost to Trump in the Republican primary, has carved out a role as a foreign policy expert and hawk on Capitol Hill, and may see his interest in global issues as a way to restore momentum in his political career.
He opened up by asking Tillerson whether he considered Russia's air attacks on civilian areas of the formerly held rebel city of Aleppo in Syria amounted to violations of the rules of war and war crimes.
"Those are very, very serious charges to make, and I would want to have much more information before reaching a conclusion," Tillerson, said.
Rubio then narrowed in on the issue of Russia, and the new administration's plans to try to improve strained US relations with the Kremlin.
"Mr. Tillerson, do you believe that Vladimir Putin and his cronies are responsible for ordering the murder of countless dissidents, journalists and political opponents?" Rubio asked in the Senate Foreign Relations Committee hearing.
Tillerson replied: "People who speak up for freedom and regimes that are oppressive are often at threat and these things happen to them. In terms of assigning specific responsibilities, I would have to have more information."
Rubio was not impressed.
"None of this is classified, Mr. Tillerson. These people are dead."
The former ExxonMobil boss replied: "Your question was people who were directly responsible for that. I'm not disputing these people are dead."
Rubio and Tillerson also clashed on Saudi Arabia when the Florida senator asked whether he was aware of human rights violations, including the treatment of women in the oil-rich kingdom.
The secretary of state nominee argued that though progress towards values the United States would support was being made, it was too slow.
The tension between strategic interests and US morale imperatives was also in play in Rubio's exchange with Tillerson on the Philippines, where a drugs war orchestrated by President Rodrigo Duterte has resulted in the deaths of thousands of people in extra-judicial killings.
Tillerson said that he would rely on facts that would be available to him as secretary of state before weighing in, causing Rubio to pounce, noting that Duterte's claims of responsibility for the extra-judicial killings were reported in major newspapers.
Tillerson argued that it was important that the US retain the Philippines as an ally in a region marked by rising tensions with China, then allowed, under intense pressure from Rubio, that Duterte's actions did not appear appropriate.
"If the facts are in fact supportive of those numbers and those actions, then I don't think any of us would accept that as a proper way to deal with offenders, no matter how grievous the offenses may been," Tillerson replied.
At points in the hearing, Tillerson appeared to appreciate that his answers were not cutting much ice with Rubio, and that he needed to try and bring him around.
"There seems to be some misunderstanding that somehow I see the world through a different lens," Tillerson told the Florida senator. "I share all the same values that you share and want the same things for people the world over in terms of freedoms. But I am also cleared-eyed and realistic about dealing in cultures, these are centuries long cultures, cultural differences."
He added, "It doesn't mean we can't affect them and affect them to change."
But Democrats, keen to draw some early blood against the Trump administration, sensed Tillerson was in a tough spot on human rights questions.
"It will be a surprise to a lot of people coming out of this hearing that you aren't ready today to call President Duterte a violator of human rights or to call what is happening in Saudi Arabia a named violation of human rights under international law," Democratic Sen. Christopher Murphy of Connecticut said.
Again, Tillerson said that he was not going to make such judgment until he had seen all the facts, but added: "My standards are no different than yours."
He then raised Democratic eyebrows further when he used a similar argument to dodge questions about whether he would oppose any plans by Trump to draw up a Muslim registry.
"I would need to have a lot more information around how such an approach would even be constructed," Tillerson told New Hampshire Democrat Jeanne Shaheen.
Rubio later told reporters that he would have to take time to consider his response to Tillerson's answers.
"If we are going to have moral clarity in our foreign policy we need to be clear, and I don't want to see us move towards a policy where human rights matters when nothing else matters ... when something more important isn't standing in the way," Rubio said.
Former US Defense Secretary Robert Gates, who served under both Bush and Obama and recommended Tillerson to Trump, defended his friend. He said Tillerson was being "properly cautious" and that he had less freedom to talk about human rights than Rubio.
"If a secretary of state makes a pronouncement about a country or about an individual, then there are legal implications in terms of actions the United States has to take," Gates told CNN's Jake Tapper.
"It seems to me he is trying to communicate that he has completely shared values with those senators," he said, "but if he takes this job ... he is going to end up having to make some decisions that have very real implications for our relationships with those countries."
Human rights advocates, however, expressed more concern.
"Rex Tillerson's reluctance to acknowledge human rights abuses by Russia, Saudi Arabia, and the Philippines raises serious questions about whether he can effectively serve as secretary of state," said Sarah Margon, Washington director of Human Rights Watch.
"Tillerson's claims that he cannot pass judgment on these counties' abuses until he has access to US intelligence briefings ignores the US government's own previous findings and suggests that Tillerson is either ill-informed or apathetic to human rights issues worldwide," she said.