BEIRUT (AP) — President Donald Trump's 59-missile message to Syria — the use of chemical weapons will not be tolerated — may well resonate with Bashar Assad.

But to truly change the game in a catastrophic, six-year civil war, the U.S. will have to show resolve in the face of potential conflict with Russia. Whether President Donald Trump will do that is anyone's guess, because Friday's missile attack contradicted so much of what was expected from his young administration.

Trump's own campaign themes hinted at an inward-looking if not isolationist America. It was especially striking because Trump had played a big role in what seemed to be the world community's gradual acquiescence to the Syrian president remaining in power as a sort-of "least bad option."

And conventional wisdom held that humanitarian issues would take a back seat to hard-edged national self-interest now. Yet Trump seemed moved to action by the suffering of innocents — the chemical attack on the town of Khan Sheikhoun, which killed 87 people, including 31 children. Syria has denied responsibility, though its denials have been widely disbelieved.

In a lesser surprise, Trump also presented a mercurial side, reacting viscerally to an event that, while tragic, was hardly a surprise. In doing so, the U.S. president has stoked tensions with Russia as well — a striking about-face from the past year in which Trump's affinity for and entanglements with Vladimir Putin have conjured up mockery and scandal. For Trump, there may be political value there as well.

Viewed in that light, Trump's first major foreign-policy decision might carry lessons far beyond Syria or the Russians. From North Korea to China, from Mexico to Germany, any leader nursing a potential beef with Trump's America will likely take note of hints of activism, idealism or risk-taking.

Assad is plainly determined to wipe out the resistance in the northern region of Idlib, the last major stronghold of rebels who are not associated with the Islamic State group. His successful recent campaign in Aleppo shows he is willing to brutalize a population and destroy much of a city to achieve such a goal — and he does not need chemical weapons for that.

Was the early-morning attack just a one-off response to warn Assad not to use chemical weapons again? If so, it might work but not change the direction of the war — and that direction at present favors Assad. It will then ultimately be viewed as something of a face-saving move at best.

But if it heralds a more aggressive U.S. policy to preventing all abuses or even remove Assad, that's a potential game-changer that risks confrontation with his forces on the ground and with Russia in the skies.

Here are some factors to consider:

ASSAD'S POWER IS NOT CURTAILED

The U.S. Tomahawk missiles hit the Shayrat air base, a small installation with two runways, where aircraft often take off to bomb targets in northern and central Syria. The base is important but not critical to Assad's ability to continue fighting rebels in opposition areas.

His air superiority provides his advantage in the war, and he still has conventional weapons at his disposal as well as more than a dozen other air bases and a sophisticated air defense system. He still has a large if tired standing army, the Lebanese militia Hezbollah fighting alongside him, the Russians ruling the skies on his behalf and the Iranians to supply and advise him.

So the question is whether the line that Trump has drawn in the sand extends beyond chemical weapons to include mass killing of civilians.

THE RUSSIA FACTOR

The Syrian chemical weapon attack and U.S. missile strike have soured relations between the U.S. and Russia, which condemned the move as "aggression" and suspended crucial coordination with the United States in Syria's congested skies. Russia has strongly backed Assad, and if Trump now turns against him that creates a conflict in one of the world's combustible arenas.

There are already hundreds of Marines, Rangers and advisers in northern Syria for the fight against IS. Could these relatively stealthy forces be beefed up, and turned against Assad if he needs further deterring? The potential for a quagmire that pits the U.S. against Russia is clear.

"The risks of a direct military confrontation of Russia and the U.S. have risen significantly," Andrei Kortunov, the director of Russian International Affairs Council, said in remarks carried by the Interfax news agency Friday. "Whether or not it could lead to WW III depends on how responsible the leaders are."

But if things continue to deteriorate, the curious "bromance" between Trump and Putin may soon be a thing of the past. Indeed, some in Russia see a move to counter the impression of Trump in the thrall of Putin. The strike was intended to "show Trump critics that he doesn't have a pro-Russia stance and is ready to take a tough course regarding Moscow," said Sergei Rogov, the director of the U.S. and Canada Institute, a Moscow-based think-tank.

But there could be a more complex maneuver in the works as well. Just a day before the strike, Putin's spokesman said Russia's support for Assad is not unconditional. Dmitry Peskov also said Russia demands a full investigation of the suspected chemical attack before any United Nations action — but the nuanced message did leave the impression of a possible cooperation. If they colluded somehow to remove Assad and end the war, Trump and Putin might both be cast as statesmen.

THE FIGHT AGAINST ISLAMIC STATE

Though Russia announced it would suspend the so-called "deconfliction line" — the communication link between U.S. and Russian military officials that has protected pilots flying missions over Syria — American officials insisted the line had not been cut, and conversations were ongoing. An end to that dialogue would complicate the international coalition's fight against the Islamic State group and make the frequent airstrikes over IS-held areas riskier.

A total break with Assad also entrenches one of the main impediments to success against IS in Syria: The coalition lacks a government-level ally on the ground. That's a stark contrast with Iraq, where the coalition is allied with both the Iraqi government and the Peshmerga forces of the autonomous Kurdish zone in the north.

In Syria the coalition depends largely on Kurdish irregulars and air power, and there are real questions about whether that will suffice to dislodge the jihadis from Raqqa and the other towns they hold in the northeast. Trump appeared to have been inching toward considering some sort of cooperation with the Russians and implicitly Assad in the endgame against IS.

If this week's events have wiped out the chance, that might be the most profound impact of all.