Council Guardian — ruling 1

The vote happens as the ability resolves. Until this happens, Council Guardian doesn't have protection from any color. Spells and abilities may target Council Guardian as normal in response to its enters-the-battlefield ability, but not in response to the vote. Once players have started voting, it's too late to respond.

Council Guardian — ruling 2

If Council Guardian is not on the battlefield when its ability resolves, the vote will still take place; it simply won't have any effect. However, cards that care about voting (for example, Grudge Keeper) will still see the vote.

Council Guardian — ruling 3

Because the votes are cast in turn order, each player will know the votes of players who voted beforehand.

Council Guardian — ruling 4

You must vote for one of the available options. You can't abstain.

Council Guardian — ruling 5

No player votes until the spell or ability resolves. Any responses to that spell or ability must be made without knowing the outcome of the vote.

Council Guardian — ruling 6

Players can't do anything after they finish voting but before the spell or ability that included the vote finishes resolving.

Council Guardian — ruling 7

The phrase "the vote is tied" refers only to when there is more than one choice that received the most votes. For example, if a 5-player vote from among three different choices ends 3 votes to 1 vote to 1 vote, the vote isn't tied.

Council Guardian : règles, fonctionnement et interactions (MTG)

Council Guardian is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Will of the council — When this creature enters, starting with you, each player votes for blue, black, red, or green. This creature gains protection from each color with the most votes or tied for most votes.

How it works : Council Guardian

Original English text — Wizards of the Coast / Scryfall

#1May 29, 2014· Wizards of the Coast
The vote happens as the ability resolves. Until this happens, Council Guardian doesn't have protection from any color. Spells and abilities may target Council Guardian as normal in response to its enters-the-battlefield ability, but not in response to the vote. Once players have started voting, it's too late to respond.
No other card is named in this ruling.
#2May 29, 2014· Wizards of the Coast
If Council Guardian is not on the battlefield when its ability resolves, the vote will still take place; it simply won't have any effect. However, cards that care about voting (for example, Grudge Keeper) will still see the vote.
No other card is named in this ruling.
#3May 29, 2014· Wizards of the Coast
Because the votes are cast in turn order, each player will know the votes of players who voted beforehand.
No other card is named in this ruling.
#4May 29, 2014· Wizards of the Coast
You must vote for one of the available options. You can't abstain.
No other card is named in this ruling.
#5May 29, 2014· Wizards of the Coast
No player votes until the spell or ability resolves. Any responses to that spell or ability must be made without knowing the outcome of the vote.
No other card is named in this ruling.
#6May 29, 2014· Wizards of the Coast
Players can't do anything after they finish voting but before the spell or ability that included the vote finishes resolving.
No other card is named in this ruling.
#7May 29, 2014· Wizards of the Coast
The phrase "the vote is tied" refers only to when there is more than one choice that received the most votes. For example, if a 5-player vote from among three different choices ends 3 votes to 1 vote to 1 vote, the vote isn't tied.
No other card is named in this ruling.