When President Donald Trump took office less than three months ago, few would have predicted that he would find himself so quickly launching military strikes against Syria. Since January, his administration has been quietly reducing support for Syria’s rebels, seemingly opening the door for an eventual settlement that might leave Syrian President Bashar al-Assad in charge.

U.S. President Donald Trump is shown in an official White House handout image meeting with his National Security team and being briefed by Chairman of the Joint Chiefs of Staff General Joseph Dunford via secure video teleconference after a missile strike on Syria while inside the Sensitive Compartmented Information Facility at his Mar-a-Lago resort in West Palm Beach, Florida, U.S. April 6, 2017. White House Press Secretary Sean Spicer stated that this image has been digitally edited for security purposes when he released the photo via Twitter on April 7, 2017. The White House/Handout via REUTERS

None of that was necessarily changed by Thursday night’s missile strikes against the air base believed responsible for a suspected nerve gas attack barely 72 hours earlier. In taking such aggressive action so quickly, however, Trump has sent what he sees as a strong, robust message of U.S. resolve – not just to Damascus but also other potential U.S. opponents including Russia, China and most particularly North Korea.

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Some kind of action was probably inevitable – and had Barack Obama still been in the White House, he might have taken a similar step. The Russia-brokered deal that averted U.S. military action after the 2013 chemical strike near Damascus was, after all, predicated on Syria giving up its poison gas stockpiles. The government in Damascus conducted high-profile handovers of what it said was all of its chemical stocks, and signed the Chemical Weapons Convention. Such an egregious, unmistakable breach of that deal was going to have to be punished.

The speed with which Trump ordered the strikes – and therefore the element of surprise – does seem to be a shift from the Obama administration, which often discussed such actions openly in advance.

In hitting just a single air base, the overnight strikes were also much more limited than the military action Washington was considering after the 2013 chemical attack. That would likely have involved an overwhelming assault on Syrian air defenses and other facilities, an action that would have been deliberately designed to undermine Assad’s grip on power but would not have been enough to topple him.

U.S. actions have infuriated Russia, which compared them to the 2003 invasion of Iraq. The United States appears to have been careful to avoid inflicting any casualties on Russian forces in Syria, however. That is in dramatic contrast to some of the plans a potential Hillary Clinton administration was said to have been considering, which would have included imposing “no-fly zones” that could have seen U.S. jets shooting down Russian aircraft.

The first question now is what this means for the U.S. policy toward Syria. In the run up to this week’s chemical strike, both U.S. Secretary of State Rex Tillerson and Defense Secretary James Mattis had suggested Washington no longer regarded Assad’s removal as a priority. It remains to be seen if that is still the case. It’s certainly possible that the Trump administration could shift back towards the approach taken by its predecessor, supporting rebel groups and doing what it can to undermine those in charge in Damascus.

For now, however, that seems relatively unlikely. The Trump administration has made it clear that its main priority in Syria continues to be tackling Islamic State, with an assault gradually looming on that group’s de facto capital of Raqqa.

Most importantly, the United States still has no credible way of bringing down Assad, should it wish to do so. It has no appetite for a troop-heavy intervention, and Trump has repeatedly stressed that he believes the lessons of Iraq and Libya are that removing regional strongmen is often a bad idea.

For now at least, this strike seems to have been a limited punishment, not the start of another U.S.-backed Middle East regime change.

The broader ramifications, however, go much further.

Perhaps the most important second-tier message of the strikes will be for North Korea – and its primary backer China, whose president Xi Jingping is meeting Trump this week in Florida. The Trump administration would like the threat of military force to persuade North Korean leader Kim Jong Un to slow or halt his country’s nuclear and missile development. That still seems unlikely – but Thursday night’s events increase the credibility of the U.S. threat.

It will also have been noticed in Iran, which has scaled back its nuclear development in the face of U.S. military threats and sanctions under a deal Trump has said is insufficiently robust and which he wants to renegotiate.

The most important lasting effect when it comes to geopolitics, however, may be on U.S.-Russia relations. It is unclear whether Moscow had advance knowledge of this week’s chemical strike, but it certainly is angry at U.S. actions since. That sends a stark message that the administration may take a tougher line with Moscow that many anticipated, despite – or perhaps in part as a result of – the ongoing suggestions that Russia intervened in the U.S. election to try to help Trump.

That may also be a sign of shifting sands in Washington. This week saw presidential adviser Steve Bannon’s dismissal from the White House National Security Council. Bannon’s ousting was already seen to have strengthened the hand of the newly appointed and highly respected National Security Adviser Lieutenant General H.R. McMaster.

Thursday night’s strike may be the clearest sign so far of the “McMaster-isation” of Trump foreign policy: well-defined, limited-but-decisive action with a relative clear, simple goal.

At worst, though, critics are describing it as yet another sign of the president’s impulsive behavior, a “shoot first and ask questions later” approach.

Either way, if there is to be a “Trump doctrine” for foreign policy intervention, Thursday night’s missile strikes will almost certainly be seen as the start of it.