How to create a view using the References module?
You could achieve your goal by building two views 

The first is the view you have build with relationship to politicians content type, Add new field gets the politician id tagged in that video

The second is a view that gets videos for politicians ids sent as a contextual filter 


  that accepts multiple values by checking that checkbox as in the picture
  


Install  that module views field view that enables you to embed a view inside another view as a field

Add new field in the first view that embed the second view and send the politicians ids as tokens to that view

Now you could achieve your goal