But it sounds oddly in my anarcho-libertarian Jesus-following soul, which quails against it.
Perhaps that's because ally, unlike comrade, does not just assume a common goal or purpose.
The term "ally" assumes a common struggle against a common enemy. It is, as a term, largely representative of the power dynamics between nation-states. Allies go to war together. Allies share common economic goals. That form of relationship is about power and power dynamics, writ into a set of established and negotiated expectations. Allies have rules and contracts and treaties that establish their alliances, which serve the shared interests of both.
Again, the word has to do with the dynamics of power and self-interest, not organic affinity and appreciation.
Canada, on the other hand, is a friend. The kind of friend who breaks into your national song when the singer's mike fails at a hockey game. The kind of friend with whom you don't really worry about boundaries, because you trust each other so much those boundaries really don't matter. You can be completely yourself and unafraid with a friend. This is not true with an ally.
Among the wisest of the secular ancients, that's why friendship was considered among the highest of the virtues. Philia, that natural and volitional affinity, was a relationship of complete, freely given trust between one person and another. Being an ally is a more sterile, formalistic, and mechanical form of relation, one in which lists of rules and trigger-avoidance-protocols define a carefully negotiated exchange.
And for those who follow the Nazarene as their Teacher in all things, the term "ally" sounds with a peculiar dissonance against the radical command to both love and friendship. "A greater love has no-one than this," says Jesus, as he swore his life to his friends. Not his "allies." The Greek word for "ally" does not appear in any of the teachings of Jesus, nor does it occur in any of the Epistles.
It's also challenging, honestly, to integrate the conflict-assumption of the "ally" concept into the radical agape ethic taught by the Nazarene. Sure, one can have enemies, those ruled by brokenness and the injustices created by our hunger for power.
But the idea that your calling in existence is to go to war with those who your allies war with? It stands in tension with the ground of the most fundamental ethic of Christian faith. It is difficult to be authentically Christian and part of that form of binary relation. Attacking and tearing down are not the methodology of the Way.
Yeah, I know, there's that one overturned table episode that's everyone's favorite conflict-prooftext, but last time I checked, an overturned table is not the defining symbol of the Christian ethic. Neither can we create easily demonizable caricatures of those who inflict injustice, even as we oppose injustices. That reflects neither the complex agape ethos of Jesus nor the justice-orthopraxis of soul-force satyagraha.
It is why, if they approach their commitment to discipleship seriously, Christians make somewhat awkward allies in a conflict. They cannot be trusted in a fight, because their commitment to grace and mercy is too radical.