Useful idiot and fellow travelers are terms used by Russian intelligence. They refer this way to those who are useful to the Kremlin. Assets are those who they directly control. As to Tucker, you can go and watch him every night.

Here, The Daily Beast got the goods on russia media and their memo promoting him. I litearry had to come to the computer since the Ipad does not allow me to link for whatever reason

https://www.thedailybeast.com/russian-media-told-to-promote-tucker-carlson-as-much-as-possible-report-says