[zarf]

Some folks can't get it through their heads that times change and that each election cycle is a different animal.

[GSlob]

'Some folks can't get it through their heads that times change and that each election cycle is a different animal."
To get anything through one's head:
First of all, that head must be there for anything to get through it; and it must be a head, and not some other, rather different part of anatomy at the other end of alimentary channel;
Secondly, even if it is a head, it cannot be too dense, or nothing would get through it anyway.