The most common and most likely answer to this crossword clue is the 9 letter word DEMOCRACY
D
E
M
O
C
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A
C
Y
More clues leading to the result DEMOCRACY
- Protest and moan about bill in country such as ours
- Incomplete farce maybe turned titillating – it gives people what they asked for!
- Protest and shout about a cold form of government
- Ruling based on popular decisions
- Damaged D Cameron cut short premiership of country before end of July, power being vested in voters
- Protest about naughty form of government
- Choice of government is a brief demonstration and shout about bill
- Protest by drivers in Mediterranean island — expression of popular will?
- Protest about risqué form of government
- Funny play mostly about spirited India, say
Buddy explains!

The straight part
We know that "power being vested in voters" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case power being vested in voters = democracy.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DEMOCRACY mean?
DEMOCRACY noun- Rule by the people, especially as a form of government; either directly or through elected representatives (representative democracy).
- A government under the direct or representative rule of the people of its jurisdiction.
- Belief in political freedom and equality; the "spirit of democracy".