Penetrate American heartland to eliminate leader (5)
I believe the answer is:
enter
'penetrate' is the definition.
(I know that penetrate is a more specific form of enter)
'american heartland to eliminate leader' is the wordplay.
'american heartland' becomes 'nter' (I can't explain this - if you can you should believe this answer much more).
'to' says to put letters next to each other (I've seen this in other clues).
'leader' says to take the initial letters.
The first letter of 'eliminate' is 'e'.
'nter' after 'e' is 'ENTER'.
Can you help me to learn more?
(Other definitions for enter that I've seen before include "Move into" , "Get in" , "Gain access to" , "Go in - set down" , "submit?" .)