Bashar al-Assad, the president of Syria, might have great contempt for the sanctity of human life, but he is not a reckless strategist. Since 2011, he has prosecuted an uncompromising war against his own population. He has committed many of his most egregious war crimes strategically—sometimes to eliminate civilians who would rather die than live under his rule, sometimes to neuter an international order that occasionally threatens to limit his power, and sometimes, as with his use of chemical weapons, to accomplish both goals at once. When he does wrong, he does it consciously and with intended effect. His crimes are not accidents.

The Syrian regime’s suspected chemical-weapons attack on Saturday in Douma, a suburb of Damascus, suggests that Assad and his allies have accomplished many of their primary war aims, and are now seeking to secure their hegemony in the Levant. But two major factors still complicate Assad’s plans. One is Syria’s population, which to this day includes rebels who will fight to the death and civilians who nonviolently but fundamentally reject his violent, totalitarian rule. The second is President Donald Trump, who has expressed a determination to pull out of Syria entirely, but at the same time has demonstrated a revulsion at Assad’s use of chemical weapons.

Almost precisely one year ago, Assad unleashed chemical weapons against civilians in rural Idlib province, provoking international outrage and a symbolic, but still significant, missile strike ordered by Trump against the airbase from which the attacks were reportedly launched. Assad’s regime was responsible for the attacks and its Russian backers were fully in the know, later evidence suggested, but Damascus and Moscow lied wantonly in their hollow denials.

This weekend, it appears, Assad’s regime struck again. Fighters in Douma refused a one-sided ceasefire agreement, and haven’t buckled despite years of starvation siege warfare and indiscriminate bombing. In what has become a familiar chain of events, the regime groomed public opinion by airing accusations that the rebels might organize a false-flag chemical attack in order to attract international sympathy. An apparent chemical attack followed, killing at least 25 and wounding more than 500, according to unconfirmed reports from rescue workers and the Union of Medical Care and Relief Organizations. The Syrian government and the Russians have once again blamed the rebels, knowing that it will take months before solid evidence emerges, by which point most attention will have turned elsewhere. The pattern is by now predictable. In all likelihood, solid, independent evidence will soon emerge linking the attacks to the Syrian regime.

Assad already has unraveled the global taboo against chemical weapons, in the process exposing the incoherence of the international community. Syria has exposed the international liberal order as a convenient illusion. Western bromides of “never again” meant nothing when a determined dictator with hefty international backers committed crimes against humanity.

Why now? This latest attack in Ghouta, if it holds to the pattern, makes perfect sense in the calculus of Assad, Vladimir Putin, and Iran’s Supreme Leader Ayatollah Ali Khamenei. The successful trio wants first and foremost to subdue the remaining rebels in Syria, with an eye toward the several million people remaining in rebel-held Idlib province. A particularly heinous death for the holdouts in Ghouta, according to this military logic, might discourage the rebels in Idlib from fighting to the bitter end. Equally important, however, is the desire to corral Trump as Syria, Russia, and Iran did his predecessor, Barack Obama.

After the humiliating August 2013 “non-strike event,” when Obama changed his mind about his “red line” and decided not to react to Assad’s use of chemical weapons, the Syrians had America in a box. The White House signed up for a chemical disarmament plan that proved a farce. By the time the agreement had unraveled and Assad was back to using chemical weapons against Syrian citizens, the public no longer cared and Obama was busy discussing his foreign policy legacy.

Trump’s Middle East policy remains a mystery. He has long appeared unconcerned with rising Russian power in the Middle East, but today tweeted that there would be a “big price” for Russia, Iran, and Syria to pay. He seems to prefer a smaller U.S. military footprint, talking repeatedly about pulling troops out of Syria and Iraq. He’s savaged the deal that shelved Iran’s nuclear program, and doesn’t appear impressed by the shabby chemical-weapons agreement in Syria. He doesn’t seem interested in a long-term strategic engagement in the Arab world, but he’s also not interested in propping up the status quo. His reaction to the Khan Sheikhoun attack a year ago aligned with these preferences: He abhorred the attack and spoke with uncharacteristic humanity about the children killed by Assad, and ordered a pointed but limited response. He wasn’t interested in escalating or intervening against Russia or Assad, but he also had no interest in pacifying or reassuring them.

One result of Trump’s confusing Syria policy is that Assad and his backers can’t quite be sure what America is planning—a pullout or a pushback. Hence another chemical attack, which will test the range of America’s response and, perhaps, will paint Trump into the same corner where Obama’s Syria policy languished.

For Assad, there is utility in such a feint, and no real risk. In 2013, he and the rest of the region braced in fear for an expected American response, which was widely expected to jolt the regional state of affairs. Assad has learned his lessons since then. No meaningful American response will be forthcoming, no matter how hideous the war crime. America remains deep in strategic drift, unsure of why it continues to engage in the Middle East, and prone to spasms of hyperactivity rather than sustained attention.

Although we can’t be sure—yet—exactly what happened  in Ghouta, we can be confident that it was no accident. Assad is determined to cement his grip once again over Syria, no matter how thoroughly he has to destroy his country in order to restore it. And with Putin’s backing, he is determined to thoroughly discredit what remains of the international community and U.S. leadership. They can’t be sure what Trump will do, but their apparent cavalier use of chemical weapons on the one-year anniversary of the Khan Sheikhoun attacks suggests they’re reasonably confident that the U.S. president won’t take serious action.

This most recent attack, as tragic as it is, is no turning point. It’s more of the same from Assad and his allies, as they solidify the grisly, dangerous norms that they’ve been busy enshrining since 2013.