Proper use of the clipboard

Dear list! I'm a bit confused about Evil's interaction with the clipboard. When I set x-select-enable-clipboard to t, visual selections are copied to the clipboard as well as yanked and deleted text. However, when I set x-select-enable-clipboard to nil, neither visual selections nor yanked and deleted text are copied to the clipboard. Both behaviors seem inconsistent with what other applications do under the X window system. My understanding is that visual selections should go into the primary selection while yanked and deleted text should go to the clipboard. Is it possible to configure Evil to behave this way? My googling didn't turn up anything useful. Titus