Peter Bergen is CNN's national security analyst, a vice president at New America and a professor at Arizona State University. He is the author of " United States of Jihad: Investigating America's Homegrown Terrorists ."

(CNN) President-elect Donald Trump met Monday in Manhattan with Gen. David Petraeus who is under consideration to be secretary of state. After the meeting Trump tweeted that he was "very impressed."

Indeed, Petraeus would be an outstanding first diplomat of the United States, although Trump is reportedly also considering candidates such as former Republican presidential candidate Mitt Romney, among others.

If Petraeus were to be tapped for the job, from Day One he would be one of the most well-informed and well-qualified secretaries of state in the post-World War II era.

There would be no learning curve for the retired four-star general. Consider that Petraeus commanded US Central Command (CENTCOM) from 2008 to 2010. In many ways the CENTCOM commander has the most demanding job in the US military, because the command oversees America's wars in Afghanistan, Iraq and Yemen. The CENTCOM commander also oversees military operations and alliances with 20 countries across the Middle East and Central Asia, which means regularly meeting and working with the top officials in those regions.

Petraeus also was the on-the-ground commander in both Afghanistan and Iraq. As the commander in Afghanistan, Petraeus dealt extensively with the dozens of NATO and other countries who were part of the coalition he led there.

Counterinsurgency strategy

It was, famously, Petraeus' counterinsurgency strategy in Iraq that played a key role in reversing the endemic violence in the country in 2007. Counterinsurgency theory and practice emphasizes both military and political approaches to defeating insurgent groups.

It's worth noting that the Iraq counterinsurgency strategy was based on the 2006 counterinsurgency manual that Petraeus co-wrote with Gen. Jim Mattis, who is the leading contender to be Trump's secretary of defense. Of course, having two retired generals in the top jobs at State and the Pentagon would be quite unusual, but Petraeus and Mattis have worked well together in the past, so would be expected to work together well in the future.

This has not always been the case with the secretaries of defense and state; just think of George W. Bush's secretary of defense, Donald Rumsfeld, and his frequent clashes with secretaries of state Colin Powell and Condoleezza Rice.

For those who might be concerned that Petraeus would not play well with the diplomats at the State Department it is worth recalling that when he was the commander in Iraq he worked very closely with US Ambassador Ryan Crocker so the military campaign meshed well with the diplomatic and political goals of the United States in Iraq.

The Syrian civil war

Because of his many years of experience in the Middle East, Petraeus is also the right choice to try to untangle the greatest foreign policy problem the Trump administration will inherit, which is the Syrian civil war.

In an interview in June, Petraeus told me that Syria is like "Chernobyl ... spewing radioactive effects everywhere -- violence, instability, extremism and the tsunami of refugees into the countries of our NATO allies and European partners, causing the biggest challenge in Europe in many decades."

In the June interview, Petraeus was clear-eyed about how tricky ending the Syrian civil war is likely to be, saying, "It's gotten more and more and more difficult, obviously, as the opposition forces have fragmented, have atomized, as the Islamic State has stood up, as the al Qaeda affiliate has been established, as the Iranian Revolutionary Guard Quds Forces advisers began helping [Syrian dictator] Bashar al-Assad -- and then Lebanese Hezbollah fighters, then some Iranian forces and Shia militias, then Russian air support and special forces. This has just gotten diabolically more difficult."

When Petraeus was CIA director from 2011 to 2012, he dealt with many of the key national security issues likely to take center stage in the Trump presidency, from North Korea to combating jihadist groups. It was when he was director of the CIA that Petraeus urged the arming of the Syrian moderate opposition, which was overruled by President Obama. Historians may record this as a missed opportunity to help blunt the rise of the group that became ISIS.

Petraeus resigned from the CIA when the FBI discovered that he had given classified materials to Paula Broadwell, with whom he had had an affair.

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Petraeus has more than paid for this transgression since then, losing his CIA job and pleading guilty to a misdemeanor for mishandling classified information. That said, would Petraeus encounter opposition during his confirmation process from Republican senators who had only recently castigated Hillary Clinton for her private email server and the classified email traffic that went through it?

New role

Since leaving government four years ago, Petraeus has traveled around the globe in his job as chairman of the KKR Global Institute, which acts as a kind of internal think tank for the leading private equity firm, New York-based KKR. In this role, Petraeus has interacted with business and political leaders around the world, which has given him another perspective that supplements the senior military and intelligence posts he has already held.

Petraeus' foreign policy positions haven't always been in sync with Trump's. In the June interview, for instance, Petraeus was clear about the threat posed by Russian President Vladimir Putin, whom Trump has praised, and the continuing relevance of NATO: "God bless Vladimir Putin because he's given NATO another reason to live. Having just been in Europe, I can assure you there is new urgency about the threat posed by Putin, and the farther east you go the greater the urgency is felt. And if you're in the Baltic States or Poland, the threat indicator is blinking red."

But if his foreign policy positions haven't been fully aligned with Trump's, Petraeus avoided taking any public political positions during the presidential campaign. He did not, for instance, declare support for Hillary Clinton during the campaign, as more than 100 flag officers did.

If Petraeus is offered the top job at State he will join other senior military leaders who have had the position as America's top diplomat. Their tenures were something of a mixed bag. Two years after World War II, former Army chief of staff Gen. George Marshall became secretary of state. Marshall was one of the most successful secretaries of state ever, overseeing the Marshall Plan that rebuilt Europe and also the creation of NATO, which kept Europe secure during the Cold War.

Gen. Al Haig, who was vice chairman of the Joint Chiefs, had a relatively undistinguished career as secretary of state between 1981 and 1982. Gen. Colin Powell, who was chairman of the Joint Chiefs, became secretary of state in 2001. Powell's otherwise solid tenure at State was marred by the presentation he made at the United Nations in February 2003 justifying the pending invasion of Iraq, a presentation that was later found to be built on faulty intelligence.

There is little doubt that Petraeus would be an excellent secretary of state. In many ways it is a position he has been preparing for throughout his professional life.