Last evening, the White House released a statement warning that Syria appeared to be preparing another chemical attack:

The United States has identified potential preparations for another chemical weapons attack by the Assad regime that would likely result in the mass murder of civilians, including innocent children. The activities are similar to preparations the regime made before its April 4, 2017 chemical weapons attack.”

As we have previously stated, the United States is in Syria to eliminate the Islamic State Of Iraq and Syria. If, however, Mr. Assad conducts another mass murder attack using chemical weapons, he and his military will pay a heavy price.

Nikki Haley followed up:

Any further attacks done to the people of Syria will be blamed on Assad, but also on Russia & Iran who support him killing his own people.

— Archive: Ambassador Nikki Haley (@AmbNikkiHaley) June 27, 2017

Via the New York Times:

Daryl G. Kimball, the executive director of the Arms Control Association, said that he had not heard of Syrian moves toward more chemical attacks, but that he suspected intelligence reports had prompted the statement. Rocket attacks using sarin gas, as in the April strikes, require considerable preparation that American intelligence might well have picked up, he said.

Mr. Kimball added that he did not recall such a precise, pre-emptive public warning against a foreign government regarding banned weapons “in at least the last 20 years.” More often, such matters are handled in private diplomatic or intelligence communications, he said.

Of course, the NYT being the NYT had to toss in a couple of stinkbombs:

Several military officials were caught off guard by the statement from President Trump’s press secretary, but it was unclear how closely held the intelligence regarding a potential chemical attack was.
…
Any intelligence gathered by the United States or its allies — notably Israel, which keeps a robust watch on unconventional weapons in the Middle East — would by nature be classified. But any American president has absolute power to declassify anything he chooses to release.

Some background. Back in April, Syria launched a sarin attack on a largely civilian target. The United States responded by launching an extensive cruise missile strike which has largely put Syria’s air force out of action. It also demonstrated that Russia was either unable or unwilling to use its air defense system to help its Syrian ally as the Russians had three hours warning before the strike. Little more than a week ago, a US Navy F/A-18 dropped a Syrian strike aircraft as it was attacking anti-regime militias in action against ISIS. Russia responded by declaring it was shutting down the deconfliction hotline and declaring all Allied aircraft west of the Euphrates as hostile. Within hours it had climbed down from the threat to declare Allied aircraft hostile and within 48-hours the hotline was running. Two days after the shootdown, a USAF F-15E knocked down an Iranian drone operating in the buffer zone around the US/UK SOF base at al-Tanf. The Russians did nothing.

The second data point is that in the aftermath of the April chemical attack, a retrospective analysis of personnel and equipment movement showed that a chemical attack could have been predicted if we had been looking for the signs. The Trump-is-a-Russian-tool set, left and right, interpreted that to mean that the Trump administration had acquiesced to the strike and then retaliated based on public outcry.

My assessment is that this message has several purposes. First, it emphasizes we are not interested in regime change — right now — but we could be convinced to change our minds. Second, it puts Syria on notice that we believe they are getting ready for a chemical attack. Third, it tells Assad that we won’t limit retaliatory attacks to the delivery system as we did in April. Fourth, it warns the Russians that if they interfere they will be treated pretty much like the Syrians and specifically that we will not allow the presence of Russian or Iranian cadres prevent us from attacking targets. The overall message is that we really don’t want to extend the scope of the war but if chemical weapons are used, things will get very ugly.

The fact that it comes from the White House and hasn’t had extensive discussion with Defense is a good thing. This has Mattis and McMaster and Tillerson written all over it.