Russian toughness and determination on the battlefield are legendary, but without operational coordination, modern communications, and fire support, it amounts to little against a well defended position with U.S. advisers and firepower.  Business Insider has reported that a force composed of Russian mercenaries, Syrians, and Iranian proxy forces attacked a joint Syrian Democratic Forces (SDF)-U.S. position and suffered heavy losses, with some sources saying 300 Russian contractors were killed.

Reuters said that Assad's force of about 500 launched an attack, which included 122mm howitzers, T-55 and T-72 tanks, and multiple-launch rocket systems.  The tanks reportedly fired 20-30 rounds about 500 feet from the US-SDF base.  But then:

The US-led coalition responded with "AC-130 gunships, F-15s, F-22s, Army Apache helicopter gunships, and Marine Corps artillery," according to Lucas Tomlinson, a Fox News reporter.  CNN also reported that Himars (the US truck mounted multiple rocket launcher system), and MQ-9 drones were used in the attack.

"First of all, the bombers attacked, and then they cleaned up using Apaches," attack helicopters, Yevgeny Shabayev, a Cossack paramilitary leader with ties to Russia's military contractors, told Reuters.

USMC artillery opens fire in Syria.

The U.S. estimated that 100 attackers were killed and that only one SDF fighter was wounded.  However, Reuters cited a Bloomberg source who said the 300 Russian KIA number was "broadly correct."  Also, the Russian air force in Syria remained grounded after being warned by the U.S. coalition about the attack, but it's not known if the warning was passed to the ground troops.  I don't think I'm being too cynical here to suggest that maybe Assad didn't want to pay the full price for what up to now has been an inferior product and so cut his losses in a brutal way.

Anyway, if defeating ISIS in short order wasn't enough of an indicator, this attack shows there is a new sheriff in town, and dislodging the U.S. from Syria will be a huge undertaking for Assad and his Russian backers.

John Smith is the pen name of a former U.S. intelligence officer.