rolling over in their graves

[english-learner]

rolling over in their graves

TOBY
We scheduled it, Josh, after your smug, taunting, you know, calamitous performance on ‘Capitol Beat.’ [beat] America for better families. The AAF and Al Caldwell.Mary Marsh. I’ve invited them all for coffee this afternoon, along with a couple of speechwriters to talk about...

JOSH
What they want to hear.

TOBY
Yes. Yes, sir.

JOSH
If you listen carefully, you can hear two centuries of Presidents rolling over in their graves.

TOBY
Come to the meeting.

JOSH
No!

TOBY
Come to the meeting and be nice.


What does " rolling over in their graves" mean in the context above? I am looking for some help from native speakers. Can you give me some examples on this saying so that I can get a clear picture of it and also know how to use the phrase. Thanks a lot!!!

[Marylin]

to roll over or turn over in one's grave -here it means that the past presidents would absolutely hate listening to the speeches by the above mentioned speechwriters. They would be disgusted, appalled and shocked.