Washington (CNN) In the first six months of President Donald Trump's tenure, the US has ramped up military operations in trouble spots across the globe and is preparing to do more.

The intensified military engagement stretches from Europe through Africa and the Middle East to South Asia, and marks a striking contrast to the vision of "America First" retrenchment that Trump presented as a candidate. Some of these increases were initiated under President Barack Obama, but Trump has continued and in many cases boosted them.

The US has established a more robust and active military presence in Somalia, Yemen, Iraq, Syria and Afghanistan and is poised to become more engaged in Libya. It has sent more troops to Europe and aims to boost military spending there. In Asia, Trump is considering responses to North Korea's aggressive pursuit of nuclear weapons and missile capabilities that include military options.

The escalation marks a stark about-face from Trump's campaign declarations that the US can no longer afford to be the world's policeman, his questioning of long-held US alliances, and his dismissal of his Democratic opponent's foreign policy by calling her, among other things, "trigger happy Hillary."

The intensification has yielded some dividends, including Friday's announcement of the drone strike killing of the "emir" of a virulent ISIS offshoot in Afghanistan. In April, Trump won won bipartisan plaudits for his order to unleash a fusillade of Tomahawk missiles against Syria in retaliation for a chemical weapons attack.

But there have been setbacks, including concerns over rising civilian casualty rates and, in January, the death of a Navy SEAL in a raid in Yemen. There are also increasing questions about whether the heavy reliance on military force constitutes a strategy.

Trump's shift on foreign military engagement marks an acknowledgment of hard global realities, analysts say. But it also reflects his heavy reliance on the Pentagon and a sidelining of the State Department, which offers more varied and long-term tools for dealing with terrorism and geopolitical tensions.

"What you're seeing now on many different fronts is an accelerating emphasis on the counter terrorism strategy," said Aaron David Miller, a vice president at the Wilson Center.

Analysts add that Trump's shift also lays bare the difference between being a salesman on the campaign trail, using the pitch that will land you the sale, and more sober restrictions that come with being commander in chief.

"Trump's campaign rhetoric was largely designed to get him elected," said James Carafano, a national security analyst at the Heritage Foundation. "You can say whatever you want on the campaign trail, but when you're President you have to deal with the world as it is."

Carafano, who acted as an adviser to the Trump transition team, argues that the foreign policy taking shape is a more accurate reflection of the President's world view than the isolationist vision he projected as a candidate.

"Fundamentally, Trump is a realist and he does have values that are consistent with American interests," Carafano said. "When I say 'America First,' that means my job is to defend the vital interests of the United States. None of those vital interests can be protected here in the United States; almost all of them require forward deployed work."

Certainly, the number of US troops stationed overseas has been ramped up since Trump's inauguration, along with an increased frequency of raids in particular trouble spots.

In Europe, the number of US troops has increased under Trump as part of NATO's eastern forward presence with new battalions in Poland and the Baltics. Obama made that decision, but Trump has doubled down by requesting a $1.4 billion increase for defense spending on the European Reassurance Initiative, which has increased the US security presence in Europe, to make a new total of nearly $4.8 billion.

The Middle East, where the administration has identified the fight against ISIS as a foreign policy priority, has emerged as a focal point. In March, the Pentagon said it was sending an additional 2,500 troops to Kuwait to await possible deployment to Iraq or Syria to back local forces in their fight against against the terror group.

In April, after Trump gave Defense Secretary James Mattis the authority to set troop levels in Syria and Iraq, the Pentagon announced that an additional 400 troops were being sent to northern Syria in what was described as a near doubling of manpower there. About 300 paratroopers were sent to Iraq, where troop levels hovered around 5,000.

In Afghanistan, in April, the Pentagon dropped the "Mother of All Bombs," the military's largest non-nuclear bomb, to target a tunnel system used by fighters claiming allegiance to ISIS and al Qaeda. In June, the Pentagon announced it would send an additional 3,000 to 5,000 troops to join the more than 8,000 troops already there.

In the Horn of Africa, the Trump administration has increased the number of airstrikes against an al Qaeda affiliate in Yemen -- conducting more than 80 strikes against al Qaeda in the Arabian Peninsula, or AQAP, since February, twice as many as in all of 2016.

Navy SEALS have also carried out two raids in Yemen, one in January that resulted in the death of Chief Petty Officer William "Ryan" Owens and reportedly several civilians. The second publicized raid, in May, was the deepest into the country US forces have ever gone to fight AQAP and led to the deaths of seven of its fighters.

Elsewhere in the Horn, the administration is sending conventional troops to Somalia for the first time since 1994 to help in the fight against the al Qaeda ally al-Shabab. In April, Trump also gave the Defense Department expanded authority to conduct strikes in the country.

In Libya, CNN's Barbara Starr has reported that the administration is considering a new policy that could significantly expand US involvement, including the deployment of up to 50 special operations forces and the re-opening of the US embassy.

The White House is also considering re-establishing a presence in Benghazi and a coordination center for some US forces and Libyan officials to facilitate counter terrorist intelligence sharing.

Miller, of the Wilson Center, doesn't see the ramping up of operations as "mission creep or the opening up of sixteen new fronts." Instead, he said, "what Mattis has done, it's been extremely careful and extremely deliberate," and that Trump, for all his rabble rousing on the campaign trail, is only selectively disruptive when it comes to foreign policy.

He pointed to Trump's frequent refrain that NATO countries must spend more on defense spending, an issue that Obama and President George W. Bush stressed. "He's a semi-disruptor on NATO," Miller said, "but the rest is still pretty conventional."