With the battle for western Mosul fully underway and ISIS leadership on the run, the coalition has begun preparations for its ultimate goal: seizing Raqqa in Syria. The US has begun increasing the number of boots on the ground in Syria, deploying a Marine artillery unit to boost the local militias aligned with the US:

A U.S. Marines artillery unit has deployed to Syria in recent days to help local forces speed up efforts to defeat Islamic State at Raqqa and the campaign to isolate the city is going “very, very well”, the U.S.-led coalition said on Thursday.

Coalition spokesman U.S. Air Force Colonel John Dorrian said the additional U.S. forces would be working with local partners in Syria – the Syrian Democratic Forces (SDF) and the Syrian Arab Coalition – and would not have a front line role.

The additional deployment comprises a total of 400 U.S. forces – both Marines and Army Rangers. It adds to around 500 U.S. military personnel already in Syria, Dorrian said.

Oh, you didn’t know we had combat troops in Syria? Actually, we’ve had troops in and out of Syria for some time, NBC News notes:

U.S. military leaders based in neighboring Iraq can take advantage of an existing authority to move troops in and out of both countries for short periods of time without exceeding the overall maximum level imposed by the Obama administration.

Lt. Gen. Stephen Townsend, who commands the American-led task force that is fighting ISIS in Iraq and Syria, had the authority to pull these Marines from Kuwait and send them in to Syria for a short deployment. A defense official said this deployment is part of the new effort to “accelerate the fight” against the militants.

In addition to these conventional troops, Special Operations Forces have been assisting against ISIS in Iraq and Syria for months.

Most of our forces in the region have been tasked for supporting the liberation of Mosul, but that mission should be accomplished in the next few weeks. Some forces will need to remain in Nineveh and Anbar to keep the sectarian feuds between Shi’ites and the native Sunnis from undoing all of the work of the last two years, but many of them could be free to join the one thousand or so doing the advance work for the march on Raqqa.

That is the ultimate mission — the victory which will undermine all of the theological claims of the so-called “caliphate” and discredit ISIS’ claim on Muslim loyalties around the world. Those claims are already on life support, so to speak, after ISIS lost Dabiq, a town that has a specific prophecy in regard to Islamist domination. The caliphate tried to slough off the theological implications by pointing out that the city’s control had passed to other Muslims, but the fall of Raqqa will be much more difficult to spin. A “caliph” that gets kicked out of his capital — or runs away from it altogether — isn’t much of a caliph at all.

Raqqa isn’t the only reason that the US has doubled its conventional forces in Syria. They were also put in place to keep a few of our allies apart from each other, and perhaps to boost the Kurds at the expense of the Turks, as Reuters suggests:

Turkey has lost momentum in the war for northern Syria as the United States draws on Kurdish allies in the assault on Islamic State-held Raqqa, but Ankara is still pressing Washington for a deal that allays its fears of Kurdish ascendancy.

Syrian Kurdish groups meanwhile sense Washington is now more firmly behind them than before, a shift they hope will eventually aid their ambitions for autonomy after years of persecution by the Syrian government.

The message was not lost on the Turks:

In a swipe at Washington, Turkish Prime Minister Binali Yildirim said on Tuesday it was unfortunate that some of Turkey’s allies had chosen the Syrian Kurdish YPG militia as a partner in the fight against Islamic State in Syria.

“The field in Syria at the moment is really very complicated,” said a senior Turkish official, stressing the fast-moving nature of events and the urgent need for agreement. “Anything could happen at any moment.”

The Washington Post reports that the message wasn’t intended to be subtle, either:

The latest twist in Syria’s ever more complicated war points to one of the many risks of a U.S. strategy that has prioritized the military defeat of the Islamic State at the expense of political solutions to the broader conflicts fueling instability in the wider region, analysts say.

Photographs and videos posted on social media in recent days have shown convoys of U.S. troops, including Stryker armored vehicles and Humvees, heading through the northern Syrian countryside trailing big Stars and Stripes flags. They have taken up positions in the villages north and west of Manbij, where U.S.-allied Arab forces backed by Kurds have been fighting for more than a week with U.S.-allied Arab forces backed by Turkey, according to U.S. and local officials.

The public display, unusual for a small U.S. presence of mostly Special Operations troops officially numbering just 503, is deliberate, a Pentagon spokesman, Capt. Joe Davis, told reporters this week. “We want to have a visible show that we’re there,” he said, adding that the goal is to urge all parties to “stay focused on the common enemy, which is ISIS.”

It’s a reminder that military forces are always projections of political as well as martial power. In order to shape the outcome on the battlefield, one has to be present in enough force to do the shaping.