Ruler maintaining current powers is resting (7)
I believe the answer is:
kipping
'resting' is the definition.
(kipping is a kind of resting)
'ruler maintaining current powers' is the wordplay.
'ruler' becomes 'king' (king is a kind of ruler).
'maintaining' indicates putting letters inside (inserted letters are held or maintained).
'current' becomes 'I' (symbol for electric current).
'powers' becomes 'pp' (physics abbreviation for power written twice).
'i'+'pp'='ipp'
'king' going around 'ipp' is 'KIPPING'.
'is' is the link.
(Another definition for kipping that I've seen is " crashing".)