Two colors are considered complementary if gray is produced when they are combined. Gray has no opposite. Gray can be spelled grey and still mean the same thing.
If a committee of Democrats and Republicans reach consensus, sometimes the resulting policy is gray. There is good and bad mixed together. Black and white, stirred but not shaken. The moral value is not striking or vivid.
If a committee of Democrats and Republicans reach consensus, the political culture mandates the rest of the herd to follow along. You are discouraged from engaging in independent thought and analysis. The overarching goal of unanimity is supposed to override any motivation to seek out alternatives. Challenging assumptions is perceived as an act of disloyalty. Depending on your perspective, this policy-making machine is either groupthink or progress.
Leadership is demonstrated in politics when decisions reached by consensus are still open to absorb and integrate ideas that may benefit the people we are elected to serve.