Washington (CNN) President Donald Trump's launch of two major military strikes in the last two weeks raises a question about his 2016 declaration that the US can no longer be the world's policeman: Has Trump changed his mind?

Eighty-six days into the new administration, the President seems to pivoting away from the "America First" doctrine that drove his campaign and foreshadowed a withdrawal from the world stage. Some of Trump's foreign policy decisions still seem to reflect that protectionist view -- in particular his decision to slash the budget for US diplomacy.

But Trump's recent use of military force in Syria and Afghanistan points to a possible evolution in his thinking about the use of American power and how best to wield it on the world stage.

While his embrace of military action is raising concerns in some quarters, others say Trump's shift takes the White House closer to a traditional US foreign policy.

"It's too early to suggest that we're seeing a doctrine, I don't think any president had a doctrine at this point, but certainly we're seeing more military force," said Barry Pavel, vice president at the Atlantic Council. "They are showing some evidence of an ability to learn and move toward the mainstream."

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Since his election, Trump authorized a January 29 raid against an al Qaeda affiliate in Yemen that left one Navy SEAL dead, three injured and killed more than 20 civilians. He has sent hundreds of additional troops to fight ISIS after taking office. In Somalia, Trump this week gave US Africa Command more authority to pursue the terror group al Shabaab.

the military's use of the The Syrian regime's alleged April 4 gas attack on its own civilians led Trump to order Tomahawk missile strikes against the Syrian airbase from which the regime's planes allegedly took off. And on Thursday, CNN first reportedthe military's use of the largest non-nuclear bomb in its arsenal to kill about 94 ISIS fighters in Afghanistan. Though Trump hasn't acknowledged whether he specifically authorized the attack, he did say he has authorized the military to take the measures it felt necessary.

The moves have given US power a shot in the arm, according to observers like Peter Mansoor, a retired Army colonel who served in Iraq and now teaches at Ohio State University.

"President Trump has given much more leeway to his military commanders to strike, and they're striking," Mansoor told CNN. "And I think that does send a message around the world that America's back."

It has also forced US adversaries to "have a different calculus," Pavel said. As a comparison, he pointed to President Barack Obama's 2013 declaration that chemical weapons use in Syria would cross a " red line " -- and decision not to attack after President Bashar al-Assad gassed and killed more than 1,400 people.

"Those who would like to challenge the United States in Asia, the Middle East and Europe knew toward the end of 2013 there was almost nothing the Obama administration would use military force to address," Pavel said. "They knew we had the ability, but not the will."

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Trump's decision to strike Syria "startled the Russians, and also certainly startled the Chinese and the North Koreans," Pavel said.

Asked Thursday if the strikes sent a message to North Korea , Trump said "I don't know," but added, "It doesn't make a difference if it does. North Korea is a problem. The problem will be taken care of."

North Korea, which celebrated a major national holiday Friday that it often marks with a show of military aggression, has complained that Trump policies, words and tweets "make trouble" and that the US has become "more vicious and more aggressive" under the new president.

With Pyongyang soon expected to conduct a sixth nuclear test, Vice President Mike Pence is headed to Asia this weekend, with stops in Seoul, Jakarta, Tokyo and Sydney.

Trump was also asked if he had given the green light for the military to use what's known as the "mother of all bombs" in Afghanistan. "What I do is I authorize my military," Trump said. "We've given them total authorization and frankly that's why they have been so successful lately."

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But that "total authorization" has raised concerns that Trump may be placing too much emphasis on military solutions to diplomatic problems and may be shirking responsibility along with authorization.

"I think President Trump has ceded a lot of authority to the military, a lot of decision-making power to the military, and he's quite happy to take credit for that when things go well," said Derek Chollet, a former assistant secretary of defense who is now an executive vice president at The German Marshall Fund. "The question in my mind is whether he will be willing to share accountability when things go wrong, as, unfortunately, military affairs often do."

There's a saying in the military, noted retired Lt. Gen. Mark Hertling, that, "You can delegate authority. You cannot delegate responsibility."

Hertling, a CNN military analyst, explained: "When you tell someone that you trust them to do something, you still own it as a senior commander. And as the commander in chief, Mr. Trump, doesn't get much more senior than that. He owns this and whatever happens in many different hot spots across the world."

Pavel, of the Atlantic Council, said he hoped "it's not an undisciplined use of military force, playing whack-a-mole."

Figuring out Trump's approach is perhaps more difficult than with previous presidents because of the speed with which he has done U-turns on core campaign positions

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Trump has changed his mind about the North Atlantic Treaty Organization, a core US alliance that he had dismissed on the campaign trail. "I said it was obsolete. It is no longer obsolete ," he said at a Wednesday appearance with NATO Secretary General Jens Stoltenberg.

He's gone from blasting China to declaring this week that he and President Xi Jinping "had a very good chemistry together. I think he wants to help us with North Korea." He's cooled, for now, on his goal of warmer ties with Russia.

And after suggesting Asian allies handle their own defense, he's reaffirmed the US commitment to Asian security, particularly in the face of growing North Korean belligerence.

Those reversed positions now seem to include his September 2016 declaration that "I want to help all of our allies, but we are losing billions and billions of dollars. We cannot be the policemen of the world."

Trump offered an explanation for the apparent change in his approach in an April 5 appearance with Jordan's King Abdullah. "I like to think of myself as a very flexible person," Trump said. "I don't have to have one specific way, and if the world changes, I go the same way, I don't change, well, I do change, and I am flexible, and I'm proud of that flexibility."