In a sword fight, as in politics, the combatants often attack each other's extremities (sword hand, extended foot, arm) first before venturing into body strike range. To get into killing range you must often risk being killed yourself. So sword fighters usually wait for their foes to weaken or an opening to develop.
The most singular thing about Donald Trump's wiretap accusation against Barack Obama is how he's refusing to play the game of extremities --losing a Flynn here and getting a Sessions paralyzed there -- and getting right into lethal range. Trump's gone right past Schumer, ignored the surrogates and gone straight for the former president himself.
Remember that old saw, that if you strike at the king, you must be sure to kill the king?
Well, the Obamunists might have forgotten it, but Trump hasn't.
This escalation represents a real threat to Obama. Suddenly everything is out of control. Nobody would have minded much if Trump had gone after one of Obama's henchmen -- which is probably what was expected -- but none can foresee how an exchange of blades between principals will end. It is safe to say however that unless the combatants disengage someone will get hurt. It will be a terrible moment for American political civility when a king lies on the political floor. The whole point of a peaceful transition of power is to prevent a clash between kings. Yet the very tragedy the electoral process is intended to prevent is happening before our eyes.
In the alternative, Trump is clearly inside the Obama/Clinton/Progressive OODA loop, and really has been from the beginning.