On December 13 Donald Trump chose Rex Wayne Tillerson, then chairman and CEO of ExxonMobil Corp. (XOM), to head the State Department, calling him "one of the truly great business leaders of the world" and citing his "broad experience and deep understanding of geopolitics." Tillerson announced his retirement from the company the following day. On Febuary 1, he was confirmed by a Senate vote of 56 to 43, the tightest margin for that position in living memory.

Tillerson, 64, joined Exxon as an engineer in 1975 and rose through the ranks to become chairman and CEO in 2006. Trump called Tillerson's life story "the embodiment of the American dream," but skeptics have focused on the role that deal-making with Russia – as well as other nations with questionable democratic and human rights credentials – played in facilitating his rise. Exxon's history of calling climate science into question, even as its own researchers uncovered evidence of human-induced climate change, has also stoked controversy.

Trump is right that Tillerson has experience negotiating abroad, though critics point to a track record of striking deals with harsh, corrupt dictatorships such as Ali Abdullah Saleh's Yemen and Teodoro Obiang Nguema Mbasogo's Equatorial Guinea. Exxon, like other oil majors, frequently exerts the kind of foreign policy influence one would expect from a sizeable state, siding with Vietnam against China in a dispute over territory in the South China Sea, for example. In 2011, Exxon clashed with the State Department – then headed by Hillary Clinton – over the distribution of oil revenues between Iraq's regions, making a deal with the government of the autonomous Kurdistan region that was seen as undermining the U.S.-supported government in Baghdad.

Exxon's dealings in Russia have attracted the most scrutiny because they have been interrupted by U.S. sanctions. According to the company's website, Exxon has formed 10 partnerships with Rosneft, Russia's state-owned oil company. Tillerson is reported to be a close friend of Igor Sechin, Rosneft's executive chairman and de facto number two to President Vladimir Putin. Exxon struck its first deal with the Russian government in 2011. Tillerson was awarded the Russian Order of Friendship soon afterwards.

When the country annexed Crimea and invaded eastern Ukraine in 2014, the Obama administration pressured American executives to shun the Kremlin. Tillerson declined to attend an event in Russia that May, but sent a company representative. The same month, Tillerson told the company's annual meeting, "We do not support sanctions, generally, because we don't find them to be effective unless they are very well implemented comprehensibly, and that's a very hard thing to do."

Tougher sanctions in the fall required the company to stop offshore drilling in the country, but Exxon obtained a two-week extension in order to avoid a threatened Russian seizure of an oil rig. Tillerson owned 2,466,350 shares of Exxon on December 9, according to an SEC filing, which were worth approximately $237.9 million as of December 16. His holdings raised concerns that he stood to gain financially from rapprochement with Russia, since it could allow Exxon to resume its projects there.

In order to avoid a conflict of interest, Exxon announced on January 3 that if Tillerson's nomination is confirmed, two million unvested shares that would have vested over a period of 10 years will be transferred to an independently managed trust that will not invest in Exxon; the funds will become available to Tillerson according to the shares' 10-year vesting schedule. He has also committed to sell the approximately 600,000 vested shares he owns and not to work in the oil and gas industry for ten years. He will give up some other awards, reducing his overall retirement package by around $7 million to – the Wall Street Journal estimates – approximately $180 million. Prior to his nomination, he was expected to retire in March.

The company elected Darren Woods to replace Tillerson as chairman and CEO on January 1.

Initially, there were concerns that Tillerson's ties with Russia could scupper his chances of taking over from John Kerry. Florida Republican Senator Marco Rubio tweeted on December 11, "Being a 'friend of Vladimir' is not an attribute I am hoping for from a #SecretaryOfState." Arizona Senator John McCain expressed similar misgivings, but no Senate Republican ended up voting against the confirmation.

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