opinion maker
opinion former
fugleman
Johnny-one-note
bell cow
kingmaker
opinion leader
inspirer
galvanizer
galvaniser
forewit
sheeple
leaderlike
torchbearer
guru
big wheel
statesperson
power broker
poobah
coryphaeus
pied piper
spear carrier
coryphée
ultracrepidarian
hegemon
chief
opinionizer
corypheus
demagogue
king of the castle
leadership
standard-bearer
voicer
timeserver
fellow traveller
important person
leaderish
personage
influential person
heretog
persuasion
bellwether
the organ grinder, not the monkey
politicker
election
swayful
captain
lobby
helm
possess