Drunk - on power, that is. Like some potatoes? (3,4)
I believe the answer is:
pie eyed
'drunk' is the definition.
(I've seen this before)
'power that is like some potatoes?' is the wordplay.
'power' becomes 'p' (symbol in physics).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'like some potatoes?' becomes 'eyed' (I am not sure about this - if you are sure you should believe this answer much more).
'p'+'ie'+'eyed'='PIE-EYED'
'on' is the link.
Can you help me to learn more?
(Another definition for pie eyed that I've seen is " Drunk".)