I think @Mhmdgomma is right, Views Field View module is useful here.
Furthermore, it can be done with one view, albeit containing more than one display.
We will create one view with two displays.
One serves as the video overview page, the other display is used to pull in the related videos.
Start with installing the Views Field View module to achieve your one-view goal.
Create the view with the displays
- Create a view "Videos" with a page display to display your video nodes. I named the page display "Overview Page".
- Create a block display for that view. I named the block display "Related Videos Block".
Configure the Related Videos Block
- Create a Relationship to field_politicians in video nodes. Do not pick the reverse reference.
- Create a Contextual Filter with Content: NID, which uses the relationship field_politicians and allow multiple values.
- Create another Contextual Filter with Content: NID, without a relationship, set it to exclude.
Test the block display by entering a NID from a politician node into the "Preview with contextual filters" field. You should see a list of videos tagged with this politicians NID.
Configure your Overview Page
- Create everything you like to display for your video nodes
- Create another field from field_politicians, exclude it from display, use the Node ID Formatter, and display all values on one row with a comma separator and no additional space.
- Create a field from Content: NID and exclude it from display. This is the current video nodes node id.
- Create a field Global: View (from the Views Field View module), embed the current "Videos" view. As display, pick the "Related Videos Block".
- Configure the Contextual Filter by using the provided Replacement Patterns. My configuration ended up being "[%field_politicians_1]/[!nid]".
The first parameter is the rendered output from the politicians field, a comma separated list of politician node ids.
The second parameter is the video nodes NID, used to remove the current video from the list of related videos.
Optionally add a Contextual Filter with Content: NID to display a single video with its related videos, or create another display for this detail view. If you enter a video node NID, you should see that single video with its related videos.