Like the Senate, you often need someone who can break ties. A team with an even number of technical people can get deadlocked on a decision. If the boss can’t or won’t step in, it can make for a miserable experience.
If I've learned anything from watching the Senate, it's that 51/49 doesn't drive forward progress. Those 49 will do everything in their power to undermine the 51. If you find your team deadlocked on decisions and you think the way forward is to find a tie-breaking vote, I have bad news for you.
Often all it takes is a qualitative comment that one could mistake for leadership, and the guy who won’t be accountable for any decisions is not leading anybody.