Boromir passionately makes the case to go to Gondor. And more, he argues for keeping the Ring and using its power in the fight against Sauron:
We of Minas Tirith have been staunch through long years of trial. We do not desire the power of wizard-lords, only strength to defend ourselves, strength in a just cause. And behold! in our need chance brings to light the Ring of Power. It is a gift, I say; a gift to the foes of Mordor. It is mad not to use it, to use the power of the Enemy against him.
This is the exact same temptation that both Gandalf and Galadriel faced, the temptation to use "strength in a just cause." But where Gandalf and Galadriel passed the test, seeing the corruption that awaited them, Boromir fails and falls, eventually trying to take the Ring from Frodo by force and breaking the Fellowship.
I don't want to over-interpret the narrative or read too much into it, but what strikes me here is how the battle against evil cannot be reduced to using power against it. Power used even in a just cause is only going to perpetuate evil. But it increasingly seems that this is the path our world is taking, the Good using power against the Bad. Using power in a just cause. We have become Boromir.
But as it says in Ephesians, our battle is not against flesh and blood. It puts me in mind of a quote I've shared here many times before from Michele Alexander, author of the book The New Jim Crow, about why she left a law school to teach at a seminary:
I no longer believe we can “win” justice simply by filing lawsuits, flexing our political muscles or boosting voter turnout. Yes, we absolutely must do that work, but none of it — not even working for some form of political revolution — will ever be enough on its own. Without a moral or spiritual awakening, we will remain forever trapped in political games fueled by fear, greed and the hunger for power.
I think she is exactly right and I think Tolkien would agree. Alexander's point underlines what is, perhaps, the great theological theme of The Lord of the Rings: that evil can only be defeated by spiritual means. And very soon in the story we'll follow Frodo and Sam as they walk this scandalous, humble, and sacrificial path.
UPDATE:
As I re-read this post, I can't help but think that Tolkien's passion for this point comes from his experience as a solider in World War I. That is, whenever Tolkien would hear a call to "use power in a just cause" his mind would immediately go to the trenches and killing fields of the Great War.
That's where Boromir leads us, into trench warfare where gun-welding angels kill each other.
