This Kushner thing is sinister as all fuck. Now there is a historical use for a back channel in diplomacy, most notably Kennedy floated proposals through John Scali via Russian Spy Alexsander Feklisov to Nikita Kruschev in order to bypass Kremlin hardliners during the Cuban Missile Crisis. Thing is though this wasn’t something set up in advance and the point of it was to bypass the more militant elements of the Soviet Government, not to bypass or subvert our own intelligence services.