Make the decision among power brokers in camera
Sometimes the need for expediency thwarts a consensus process. Make the decision among power brokers in camera, as in the storied smoke-filled rooms stereotypically associated with tycoon businessmen.
Politics come into play. You would like everyone that is involved to have a say in the decision, and in particular, would like all stakeholders to have a say in the decision. However, where, for example, team members are not viewed as having the legal power, or positional authority, or even the experience to make a key business decision, their participation in a consensus process is viewed as that of a "loose canon on deck." These team members are likely to view the decisions made by a cabal in a smoke-filled room as suspect and politically motivated, and not in the best interests of the project. Yet the rationale behind the decision may not be one that can be made public. Decisions about mergers and takeovers, about project cancellations, are likely candidates for this pattern.
This pattern must be used sparingly and only where appropriate to balance the forces in existence. Over-use can alienate the excluded roles and result in serious deterioration of ability to deliver. Making decisions about Architecture this way is asking for trouble with disaffected developers.