Late on Thursday, the United States launched a cruise missile strike against a Syrian regime airbase — the first intentional US strike on Bashar al-Assad’s forces since the Syrian war began in 2011. The strike was in direct response to a chemical weapon attack on the rebel-held town of Khan Sheikhoun on Tuesday, which killed at least 85 civilians (23 of whom were children).

After the strike, President Trump spoke to reporters to explain the administration’s reasoning for escalating America’s role in Syria’s war. There were two sentences in the statement that were absolutely critical for understanding why the administration did this, and why they hope it won’t get out of hand:

Tonight, I ordered a targeted military strike on the airfield in Syria from where the chemical attack was launched. It is in the vital national security interest of the United States to prevent and deter the spread of chemical weapons.

What’s crucial here is that Trump’s justification for launching the strike isn’t to end the Syrian civil war, or even to slow down Assad’s killing of his country’s civilians. It is a “targeted” strike designed as punishment for one specific crime: the use of chemical weapons.

The core problem with any proposed plan for intervention against Assad has always been the risk that it could get wildly out of hand, dragging the US deeper into the Syrian conflict than it was prepared to go and potentially making the already incredibly complex and bloody war even worse. Any serious intervention in Syria also carried the very real risk of killing Russian soldiers, who are in Syria helping Assad, thus potentially sparking conflict with a powerful, nuclear-armed enemy.

The Trump administration is trying to avoid this kind of open-ended commitment. By going out of his way to emphasize that this US strike targeted the exact airbase from where the chemical attack was launched, Trump is making it crystal clear that the strike is designed as a specific punishment for the recent chemical attack — and not a broader effort aimed at striking Assad until he stops bombing civilians or leaves power.

The goal isn’t to stop the bloodshed in Syria, but rather to send a message to Assad (and potentially other rogue states) that chemical weapons use is out of bounds.

This is consistent with how Pentagon spokesperson Capt. Jeff Davis described the military’s strategy in an email to press. “The strike was intended to deter the regime from using chemical weapons again,” Davis said. “The use of chemical weapons against innocent people will not be tolerated.”

It’s also how Micah Zenko, an expert on military intervention at the Council on Foreign Relations, interpreted Trump’s comments.

“Trump's statement makes it clear [that] US cruise missile strikes are for enhancing [the] international norm against chemical weapons use, not protecting Syrian civilians,” Zenko tweeted.

The implication here is that Trump has no desire to launch any more strikes unless Assad uses more chemical weapons. If Assad sticks to his normal tactics, and kills children with explosives rather than banned chemicals, then the United States will leave him alone. This attack will, it seems, be a one-off — or at least part of a relatively small battery of punitive strikes.

But limited strikes, historically, don’t always stay limited. We have no idea if this will actually stop Assad from using banned weapons, or what Trump would do if he did. And a sense of “ownership” of the Syrian civil war afterward could lead to even further US escalation.

“Tonight's strikes may deter Assad, compel Russian cooperation with US interests, [and] not lead to deeper US military involvement,” Zenko tweeted. “However, if these rosy scenarios do all occur, it would be almost unprecedented in US military interventions dating back to [1975].”

Trump’s objective appears to be limited. Who knows how long it will stay that way.