After a gruelling, aggressive and bitterly fought election campaign, in a victory which stunned the world and has been described as having no parallel in American history, Donald Trump is set to become the 45th president of the United States.

Trump, a 70-year-old billionaire reality TV star, has never held political office or served in the US military.

He ran a campaign which challenged the vision of a multi-ethnic, globalist US, and expressed his disdain for long-standing political and security alliances. He described NATO as being obsolete and stuck to his "America First" slogan which harks back to the 1940s.

President-elect Trump takes power at a time of multiple global crises. He will face challenges including an assertive President Vladimir Putin of Russia, the Syrian civil war, and the battle against the Islamic State of Iraq and the Levant (ISIL) in Syria and Iraq.

General David Petraeus has been at the centre of these global pressure points, having served as the top US commander in the wars in Iraq and Afghanistan, and later, as director of the CIA.

I think there's a resilience factor to the US government, to the US democracy, its system of checks and balances that will enable it to move forward very, very, very well.

General Petraeus, former top US commander and ex-director of the CIA

Petraeus talks to us about the challenges President-elect Trump will inherit and how US foreign policy might change under his leadership.

When asked whether it is significant that the US' traditional foes are cheering and its allies are bemused and dismayed by the election result, Petraeus says, "it's not the most welcome of developments" but that American democracy has been robust over the years and the US has seen more divisive politics in the past.

"I think there's a resilience factor to the US government, to the US democracy, its system of checks and balances that will enable it to move forward very, very, very well," he says.

What the election results revealed, he says, "is that people have to understand sentiments in the heartland and there is a disconnect between, if you will, the coast and the 'flyover areas' as they're termed - that's the heartland and that's where the election was won and lost ... that's our 'street'.

"You know, I used to get advice when I was in the Middle East all the time: Always listen to the Arab street. In fact, some leaders gave me that advice who perhaps might have listened closer to the Arab street once or twice. And here, I think it's not unwise to the listen to the heartland a little bit more clearly ... than we have in the past."

Petraeus also discusses Trump's ongoing selection of his top team and whether he would be willing to be part of it. "I don't know yet," Petraeus answers, when asked if he would serve if he is called upon.

Foreign policy and alliances

Petraeus speaks to us about the suggestions, made by Trump during his campaign, of forging closer ties to Putin and discusses whether he, as former director of the CIA, would "trust" Putin. 

According to Petraeus, the issue does not come down to trust, but understanding Putin's objectives - where they converge and diverge with those of the US.

He cites the Kremlin's support for separatists in southeast Ukraine, the seizure of Crimea and the 2008 invasions of South Ossetia and Abkhazia in Georgia as "big concerns" and the "activities in Syria also of considerable concern, in as much as some of these have clearly been part of quite indiscriminate bombing, deliberately it appears, by the Bashar al-Assad regime, and it appears also by Russian air force on hospitals and sites that are thronged with civilians."

Petraeus believes that NATO's allies - neighbours and near-neighbours of Russia - should not be concerned about whether or not the US would come to their defence, if faced with aggression by Russia.

"I think that should not be in question," Petraeus says, adding that he is "absolutely" confident the core NATO commitment would be adhered to and that he is not worried about Trump's hints of wanting to take a step back from NATO. He argues defence alliances and commitments with South Korea and Japan are "iron-clad".

"We have to see, as now the process begins of translating campaign rhetoric into foreign policy reality, and I don't have huge concerns in that particular area," he says.

ISIL and the battle for Mosul

He also discusses the fight against ISIL and the battle for Mosul, which is currently under way. 

"I think it's actually going quite well," he says. "I have said for nearly two years that there was never a question that the Iraqi security forces, with the enablers that the US and the coalition members would bring to assist, would defeat the Islamic State, which is the army that is the Islamic State; that's what came in and made short work of the Iraqi security forces in some of the areas in the north and in western Iraq as well." 

He says the battle for Mosul isn't a disaster. It is "unfolding as a textbook example of urban combat where there is a very high degree of sensitivity to damage, to innocent civilians." Demographically-speaking, Mosul lies in "very complex human terrain", and the biggest challenge will come after the battle, Petraeus says.

"There will be a struggle after this, understandably, essentially for power and resources."

When it comes to Syria, we ask Petraeus whether ISIL or Assad should be the priority for the next president.

"You can't divorce the two. Clearly, you have to prioritise, and clearly, the priority has to go after that element which is posing an external threat and of course, that is the Islamic State," he says. 

During the campaign, Trump may have boasted of himself being his primary consultant, but Petraeus says he is "well-known for reaching out, having a circle around him, who has expertise. And my suspicion [is] that you will see ... advisers selected who will indeed help him deal with the world that is out there - some of which he knows about, and some of which he's going to have to learn more about."

Middle East: Lessons learned

Finally, we ask Petraeus what he believes are the main lessons learned over the past decade and more of leading war operations in the Middle East. He lists five:

Firstly, he says, "Ungoverned spaces in the Middle East, and also frankly North Africa and Central Asia, will be exploited by Islamic extremists. It's not a question of if; it's a question of when and how big will that exploitation be."

Secondly, he says, "Las Vegas rules" (what happens in Vegas, stays in Vegas) don't apply in these locations.

"Rather they tend to spew violence, instability, extremism and, in some cases like the geopolitical Chernobyl that is Syria, they spew a tsunami of refugees," he says.

Thirdly, he believes, a response is imperative and "in responding, the US does have to lead".

He says: "The US has more of the assets that we really need, that we're seeing so useful in Iraq - manned and unmanned aerial vehicles, the precision strike, industrial-strength intelligence, fusion capability, than all of our allies and possible partners put together, times a factor of five or more. So, the US has to be engaged."

Fourth, he says, the US must ensure a "comprehensive campaign" is pursued.

Fifth, these conflicts must be understood as a "generational struggle". 

Describing the certainty of defeating ISIL, he says: "We will put a ... stake through the heart of the Islamic State without question."

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Source: Al Jazeera