Aaron David Miller is a vice president and distinguished scholar at the Woodrow Wilson International Center for Scholars and author of "The End of Greatness: Why America Can't Have (and Doesn't Want) Another Great President." Miller was a Middle East negotiator in Democratic and Republican administrations. Follow him on Twitter @aarondmiller2 . The opinions expressed in this commentary are his.

Having worked for half a dozen of his predecessors, here are several takeaways on the significance of his appointment.

A sharp break with the past

In the post-World War Two period, we've never had a Secretary of State whose entire career has been spent in the private sector without any prior government or public service.

The closest to this would be George Shultz , who worked for Bechtel between 1974 and 1982 before coming to Foggy Bottom. Prior to that, he had served as Secretary of Labor and Treasury and head of OMB.

Unlike his predecessors -- among them generals, a national security adviser, a secretary of the Treasury, a White House Chief of staff, a Senator -- Tillerson's lack of public service doesn't mean he can't do the job; indeed Exxon operates internationally on five continents and 50 countries.

While Tillerson is no Metternich or Kissinger, he knows his way around the world, many of its leaders, and certainly the political and economic oil world in Asia, the Middle East -- and of course, Russia.

In Trump's Comfort Zone

The process of picking this Secretary of State was clearly the noisiest, most public and political in recent memory. When I asked George HW Bush why he picked James Baker as his Secretary of State, the former President said it was a no-brainer -- a "gimme" in golfing terms.

Not here. The number of candidates with such diverse backgrounds reflects a clear lack of direction on what kind of Secretary of State the President-elect wanted: Romney; Giuliani; Petraeus; Corker. Tillerson entered the field rather late in the game.

I have chosen one of the truly great business leaders of the world, Rex Tillerson, Chairman and CEO of ExxonMobil, to be Secretary of State. — Donald J. Trump (@realDonaldTrump) December 13, 2016

Still, it's hardly a stretch to see that Tillerson must have impressed Trump as someone much like himself -- a stunningly successful corporate executive with mythic business success on a global scale, or to use the President-elect's words a world-class player.

Appearances are important to Mr Trump, who quipped that Mitt Romney looked like a Secretary of State. Tillerson may not have walked straight out central casting, but he clearly has a large and forceful presence that got Trump's attention. Reported endorsements by Bob Gates, Condoleezza Rice and fellow Texan James Baker certainly helped.

The Russian Connection

It's impossible now to assess how Tillerson's relationship with Putin -- particularly against the ongoing controversy over CIA's analysis of Russian interference in US elections -- will affect his confirmation prospects.

Senate Republicans and Democrats, especially on the Senate Foreign Relations Committee, are understandably pretty spun up against Putin. But unless Tillerson stumbles during the hearings and comes across as someone who's naïve and soft on Putin (highly unlikely) instead of a guy who knows just how ruthless and manipulative the Russian leader can be, I suspect the process will be rough but ultimately successful.

Unless additional information breaks on Putin's involvement in US elections or something truly damaging on Tillerson, it's hard to believe the Senate will deny the President his choice of Secretary of State. And whether Trump ends up cooperating or confronting Putin -- and both are distinctly possible -- it might be useful to have someone like Tillerson who has a sense of both Putin the man and Russia too.

Can Tillerson Succeed?

Much depends on what kind of Secretary of State Donald Trump wants. My guess is that Trump will focus on domestic affairs and preside rather than try to micromanage foreign policy. Trump will set broad parameters -- no nation building; taking allies to task if they don't reciprocate sufficiently; trying to engage Putin. Tillerson and the President's other national security appointments will have to work within them or try to influence the President and try to change them. And right now it's impossible to know who among Trump's advisers -- including his family -- will carry the most weight on foreign policy matters.

Whether Tillerson has the skills and intuitive instinct to be a successful negotiator is an open question. Clearly he has very successfully closed oil leases, contracts and various negotiations in the energy sector all over the world. But dealing with international crises isn't quite the same thing as negotiating leasing arrangements or extraction rights in country A or B, or in the case of President Trump, real estate deals.

National identity, deep existential fears, historical trauma, and religion often interact in conflicts between nations and efforts to accommodate them in ways that just aren't present in business transactions.

Based on my experience in working for a number of Secretaries of State, two things are stunningly obvious.

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First, success abroad for a Secretary of State and a President too depends on whether the world cooperates and offers up crises that can be defused and agreements that are possible to negotiate.

Second, no secretary of state can succeed unless he or she remains close to the president and the president watches his back in Washington and abroad; there are no successful lone rangers at Foggy Bottom.

James Baker summed it up nicely. He was the White House's man at the State Department; not the State Department's man at the White House. And something tells me that Rex Tillerson has already got this figured out.