GIRM WARS: Another front opens in Iowa
When the 2000 GIRM was issued (now usually cited as 2002 GIRM because it is in the 2002 Missale Romanum), a question was put to the Congregation for Divine Worship: Can a bishop, in his role as moderator of the Sacred Liturgy in the diocese, forbid ad orientem worship?
On 10 April 2000, the Congregation for Divine Worship issued an official response (Protocol No. 564/00/L) about GIRM 299 (my emphases):
This dicastery wishes to state that Holy Mass may be celebrated versus populum or versus apsidem. Both positions are in accord with liturgical law; both are to be considered correct.
There is no preference expressed in the liturgical legislation for either position.