“A DIPLOMAT that happens to be able to drill oil.” That is how Reince Priebus, Donald Trump’s incoming chief of staff, described Rex Tillerson, the boss of ExxonMobil, who was nominated this week as America’s secretary of state. In fact, Mr Tillerson, 64, is an oil driller through and through, has spent 41 years furthering the ambitions of one of the world’s largest companies, and has often sidelined the American government because he felt ExxonMobil was better able to look after its global affairs itself.

Yet he has a reputation for dependability and small-town Texan values that has enabled him to stand up to, and win respect from, notoriously slippery world leaders such as Vladimir Putin. The question is, will it help him become a good envoy-in-chief for diplomacy’s nemesis, Mr Trump? Or will he also peddle Mr Trump’s “I win, you lose” sense of international relations, with oil interests always in the back of his mind? 

For a leader of the world’s corporate elite, Mr Tillerson has parochial roots. Born in Wichita Falls, Texas, he grew up as a Boy Scout, went to the University of Texas, and rides horses in a cowboy hat in his spare time. He has worked at ExxonMobil since 1975, never lived outside America, and speaks with a drawl.

Jack Randall, a friend from university days and an oil banker at Jefferies, recounts how Mr Tillerson still spends time after work fixing up the decking on his lakeside home, despite having numerous employees who would do it for him. “He’s a regular guy who has lived the American dream,” he says. “He’s a Texan, an engineer and a Boy Scout. That is where his values come from.” 

Yet as an oilman and ExxonMobil’s chief executive since 2006, Mr Tillerson has run operations in some of the most inhospitable parts of the world, from ice-encrusted Sakhalin in the Russian Far East, to poverty-stricken Chad. That has meant dealing with populist strongmen, from Mr Putin to Venezuela’s late leader Hugo Chávez, who he has often cajoled into submission by arguing for the importance of free markets and the sanctity of oil contracts. 

In a book on ExxonMobil, “Private Empire”, author Steve Coll recounts Mr Tillerson’s early dealings with Mr Putin during efforts to rein in an unruly Russian partner, Rosneft, on the Sakhalin development. When Mr Putin offered to write an executive order pushing ahead with the project, Mr Tillerson refused, saying that the Russian president lacked the legal authority to live up to his company’s standards. Though Mr Putin “blew his stack,” he gave in to Mr Tillerson’s demands.

In a later oil era, in 2011, ExxonMobil and Rosneft struck a deal to develop oil in Russia’s Kara Sea, which Mr Putin said could lead to a whopping $500 billion of Arctic co-developments. In 2013 Mr Putin awarded Mr Tillerson Russia’s Order of Friendship. The Arctic deal was scuppered because of American sanctions against Russia, following its annexation of Crimea in 2014, which were opposed by Mr Tillerson. James Henderson, an expert on Russian oil at the Oxford Institute for Energy Studies, says the Kremlin came to respect ExxonMobil under Mr Tillerson, despite the firm’s stubborn belief in its own value system, because it was “dependable”. He says: “Exxon always makes the point very clearly that it all has to be above board. Its terms do not involve brown envelopes under the desk.” 

Mr Tillerson’s ties to Mr Putin are likely to complicate his confirmation hearings, especially amid allegations that Russian hackers interfered with America’s presidential election to help Mr Trump. But his defenders are adamant about his integrity. “The chances are better that Mother Teresa was stealing money from her charity than Rex Tillerson will do anything with Putin that isn’t in the best interests of the United States,” Mr Randall says.

What is less clear is how he will deal with America’s traditional allies, such as Europe, who fear Russian meddling in Ukraine, for example. His appointment will rekindle suspicions that American diplomacy is about securing oil and other scarce resources. NGOs allege that ExxonMobil has a poor record of promoting human rights in countries where it operates, and has flip-flopped on climate change.

Yet as well as having an oilman’s resource-hungry mindset, he could also bring useful industry traits to the State Department—and to a Trump presidency. For example, finding and drilling oil requires elaborate modelling—both of underground geologies and messy above-ground geopolitics—to make money over the long-term. He knows that such models are as likely to be wrong as well as right. Reputedly his engineering background makes him a stickler for evidence-based decision-making. He is also considered “patient and unemotional” on ExxonMobil’s side of the negotiating table.

Such traits would make him very different from Mr Trump, who lives by the gut. “Rex is not a guy who wets his finger and puts it up in the air to see which way the wind is blowing, and he’ll tell Mr Trump what he thinks,” Mr Randall says. In some respects his opinions differ from Mr Trump's, too. Though once a climate-change denier, he now believes mankind has helped cause global warming. Last year ExxonMobil supported the Paris agreement on climate change. In the past he has strongly rebuffed calls (recently supported by Mr Trump) to make America energy independent. With luck, he will not only have the tactical skills to further America’s interests abroad. He will also have the integrity to talk sense into his boss.

CORRECTION: An earlier version of this story described ExxonMobil as, "one of the world's largest private companies". This was confusing. ExxonMobil is a private in the sense that it is not controlled by a government, as many oil majors are. But it is of course publicly traded. The story now just reads, "one of the world's largest companies". Sorry.