Tillerson's challenge this week was to translate Trump's sudden strike on Syria into meaningful diplomacy by outlining the administration's policy -- and articulating a strategy to achieve it -- all in the space of a few days.
Across the table from Russian President Vladimir Putin this week, he might have been wondering what God was thinking.
Putin and his foreign secretary, Sergei Lavrov, are the most skilled diplomats of their generation in Russia. They know all the usual gambits and ruses of adversaries and have a reputation for defiance, dissembling, obfuscation, prevarication and fabrication.
In Tillerson, they are meeting someone they already have tested, back when he was running Exxon Mobile and was cutting an oil deal in the opaque Muscovite business world.
Tillerson's reputation as a tough, truthful and honest negotiator wasn't damaged by this contact. Whatever they saw in him at the time, it was sufficient to award him Russia's Order of Friendship.
Now Tillerson is after something far more valuable: Not Russia's oil, but its sense of place and importance in the world.
Tillerson is new to diplomacy. On his trips to Germany, Japan and China, he mostly eschewed contact with journalists. His early weeks on the job have not given critics much to measure him by.
The White House cut his department's budget by a quarter and emasculated his soft power war chest of overseas aid by almost 40%. Publicly, he hasn't criticized Trump, although he has acknowledged the limitations the cuts could bring.
That Tillerson emerged from his meetings with Putin and Lavrov appearing unchanged in his view of Assad's guilt is a testament to his own strength.
But Putin and Lavrov were equally unmoved by their meetings with him, doubling down, defying the allegations and calling for an independent investigation while their ambassador at the UN was simultaneously preparing to block a resolution for just such an inquiry.
What Tillerson appears to have met in Moscow is an impenetrable thorny thicket of diplomatic defenses while simultaneously realizing how few tools he has to fight his way through it. Lavrov told reporters that Secretary Tillerson "did not threaten me with sanctions, he did not threaten me with anything."
Tillerson, it seems, is in at the deep end of diplomacy, and his former friends in Russia have no interest in throwing him a lifeline.
Lavrov has, however, been clutching at Tillerson's words.
In an interview with ABC shortly before leaving for Moscow, Tillerson said: "Once we can eliminate the battle against ISIS, conclude that and it is going quite well, then we hope to turn our attention to cease fire agreements."
Tillerson continued: "We are hopeful that we can work with Russia and use their influence to achieve areas of stabilization throughout Syria and create the conditions for a political process through Geneva in which we can engage all of the parties on the way forward and it is through that political process that we believe the Syrian people will ultimately be able to decide the fate of Bashar al-Assad."
Lavrov seems to have taken that to the bank.
As the joint press conference concluded, Lavrov -- as he has done so often in the past -- let slip how he hopes things will go from here. Secretary Tillerson, he said, agrees that we can get rid of ISIS with Assad in power, but if we get rid of Assad first, we'll never get rid of ISIS.
Lavrov has done this to secretaries of state before.
At the end of a long press conference with John Kerry, Tillerson's predecessor hinted that Russia could potentially have a role clearing up Syria's chemical weapons. Lavrov seized the moment and Obama's red line disappeared
in the rear view mirror of history.
If Tillerson noticed Lavrov steal the initiative this week, he didn't let it show. He did what many seasoned diplomats have done before him when their game plan is being cobbled together on the hoof: He stayed silent and headed home.
But this confrontation is far from over.
What Trump's strike on Syria has done is draw Russia out in to the open. It has forced Russia to play a few cards from its diplomatic deck and made it clearer where Moscow really stands.
And so far it has stood by Assad's side, denying his use of chemical weapons -- although Lavrov did say that they are not wedded to him.
This was a perfect example of Russia's foreign minister exercising his finely honed diplomatic double speak. "In Syria, and I have stressed this many times, we are not staking everything on one personality, on President Assad."
Here, he suggests that there is a chance the Russians might just dump Assad.
But it's Lavrov's next sentence that experienced diplomats will have listened too more closely. His careful caveat seems to back away from what might sound attractive to American ears. "Removing or ousting a particular personality is not on our agenda."
Words he's used before that, in the past, have amounted to nothing but prevarication and the status quo.
By now, Tillerson will likely be scanning his State Department assets with renewed vigor for any and all diplomatic leverage he can find.
Tillerson's boss also is learning foreign affairs on the job. Just this week, Trump decided NATO is no longer obsolete.
Trump's new style in which he quickly gets on the front foot -- see last week's strike in Syria and this week's bomb dropped in Afghanistan -- leave Tillerson trailing in the wake of his boss's actions. It's never an easy position for a diplomat.
He is at the mercy of Trump's apparently insatiable and capricious desire to tackle every issue head on at full speed and treat complex problems as binary issues that can be solved through military muscle, bluster and bluff.
After his brief dip in the deep end of diplomacy this week, Tillerson has shown he can swim with the sharks. But he'll also be realizing how little time he's going to have in the coming months to see his grandchildren.