In Commander, does your commander retain its color identity if it's face down as a morph?

A commander's color identity is a deck-building rule, not a game-rule property that changes during play. Color identity is calculated once — before the game begins — based on the card's mana cost, color indicator, and rules text (including any mana symbols in abilities). This is defined in CR 903.4.

When a card is turned face down as a morph (CR 702.36), it becomes a 2/2 colorless creature with no name, no types, no abilities, and no mana cost for most game purposes. However, this only affects how the card is treated in the game. It does not retroactively alter the color identity that was already established at deck construction time.

Color identity is not a characteristic of the card as it exists on the battlefield — it is a property used solely to determine what cards are legal in a Commander deck (CR 903.4). Because morph's face-down rules only suppress in-game characteristics, they have no bearing on color identity.

Concrete example: You build a deck with Ixidor, Reality Sculptor as your commander (blue color identity). You legally include Willbender (a blue morph creature) in your deck. During the game, Willbender enters the battlefield face down as a 2/2 colorless creature. It is still a legal inclusion because its color identity (blue) was assessed at deck construction, not during play.

In summary: face-down status suppresses in-game characteristics (CR 702.36b), but color identity (CR 903.4) is a construction-time concept and is never affected by a card being face down.