Marines and special ops take dam 25 miles from Raqqa

The Drive:

US--backed Syrian fighters and US special operations personnel, along with a cadre of Marines, have been deployed to the al Tabqa Dam, also known as the Euphrates Dam, located roughly 25 miles west of ISIS's self-proclaimed capital of al Raqqa. The dam and the nearby town that shares its name are placed along two highly strategic routes that if left unsecured could give ISIS militants an escape route out of al Raqqa once the offensive to take back the city officially begins.

The surprise deployment to the dam was said to have been largely made possible via US airlift capabilities and fire support. Although the number of troops involved in the operation remains unconfirmed, multiple reports put it around 500.

The dam provides electricity to the region, making it an especially high-value asset, and the BBC reports that a military airbase and a detention center holding prisoners of ISIS are also nearby. The airfield in particular could provide a valuable hub of operations for aircraft and command and control assets, not to mention a firebase, if it were to be secured by US-backed forces.

Blocking the western approaches to al Raqqa may block fleeing ISIS fighters, but it also could work to block Syrian, Russian and Hezbollah troops from approaching the Islamic State stronghold. The US has executed a similar strategy to the north in Manbij, a move that has resulted in US and Russian troops staring each other down at a distance, while Turkey has said a military operation to route Kurdish fighters from the city is on the table. To call the town that is held by US and Syrian Democratic Forces—which are made up primarily of Kurdish fighters—a potential international flashpoint would be an understatement.
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There is more.

The mainstream media seems to have lost interest in the war with ISIL and is more focused on the Democrats war with Trump.

You can tell the amateurs from the Obama administration are no longer in charge of tactics and Strategy.  These moves appear to be aimed at shaping the battle space for taking the capitol of the caliphate.