Hoffman writes that a hybrid threat is “any adversary that simultaneously and adaptively employs a fused mix of conventional weapons, irregular tactics, terrorism, and criminal behavior in the battle space to obtain their political objectives.”
By "conventional weapons" I assume he means conventional military units, since irregulars, terrorists, and criminals use "conventional weapons."
Why is this considered so unique? Really, the Vietnam War was hybrid warfare with this definition.
Our troops were constantly forced to balance conventional fighting against conventional military units--requiring our forces to concentrate--and irregular warfare that required our forces to break down and spread out to separate and protect people from insurgents, terrorists, and criminals.
Don't waste so much time reinventing the wheel when we traveled so far down a road on the same invention already. By the time we left South Vietnam, the insurgency was defeated and the North Vietnamese army had been held at bay. Only a cut off of American aid and air power by Congress reversed those victories.
And even the apparent Russian innovation in 2014 of sending troops while denying involvement was partially carried out by North Vietnam which funneled troops south to eventually take over the Viet Cong (who were shredded in the 1968 Tet Offensive) to AstroTurf a mass uprising.
But at least we didn't go along with the North Vietnamese fiction, as our bombing raids on North Vietnam showed--unlike in the Donbas where we oddly seem to mostly go along with the Russian fiction that local rebels with more tanks than Germany, Britain, and France can field in their arsenal are the other side in the war with Ukraine.
Just kill "hybrid" threats the same old way enemies have always been killed. Study what we did in Vietnam.