Political coalitions emerge when the benefits of more tightly organized political action outweigh the foregone benefits of uncompromising, dispersed, and purely principles-based action. Liberals should tenaciously keep the disagreements with our coalition partners as live disagreements rather than suppressing them. Because liberalism needs to be defended not only *by* coalitions, but also *within* them while they exist and *without* them after they end.

Tribes, Coalitions, Parties
A theory of how political organizations form, cooperate, rise, and decline.
liberalism.org