tolkiens legendarium - Why Did Boromir Succumb to the One Ring?

Why was Boromir corrupted by the One Ring when the other members of the Fellowship of the Ring were not?

What was it about Boromir that he was so susceptible to the evil powers of the One Ring and the other members, while certainly aware of the temptation and allure of the One Ring, were not lured in by its evil? Did Denethor's pressure drive Boromir to claim the ring? Boromir is described in Fellowship of the Rings as a pretty big guy -- tall, very strong -- not unlike Aragorn. So why did he not have the inner strength to resist temptation when it came to the One Ring?

Answer

Boromir's downfall was pride. He was proud of the power both in himself and in Gondor, and the Ring played on that resulting in Boromir attempting to take it by force because he thought he knew best.

As Boromir himself states of his pride of Minas Tirith:

True-hearted Men, they will not be corrupted. 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 of himself:

...why not Boromir? The Ring would give me power of Command. How I would drive the hosts of Mordor, and all men would flock to my banner!'

Boromir strode up and down, speaking ever more loudly: Almost he seemed to have forgotten Frodo, while his talk dwelt on walls and weapons, and the mustering of men; and he drew plans for great alliances and glorious victories to be; and he cast down Mordor, and became himself a mighty king, benevolent and wise. Suddenly he stopped and waved his arms.

These feelings were played upon by the Ring's corrupting influence, as Boromir felt that he and Minas Tirith could use the Ring the best. Gandalf, Elrond and Galadriel are shown to be truly wise in comparison for they also knew what could be accomplished with the Ring, but did not fall to its charms.

Tolkien definitely viewed pride as a corrupting influence, as seen in his letters on the Fall of Numenor and the corruption of Sauron:

But after the rebellion of the Númenóreans, the Kings of Men, who dwelt in a land most westerly of all mortal lands, and eventually in the height of their pride attempted to occupy Eressëa and Valinor by force, Númenor was destroyed

...and...

In my story Sauron represents as near an approach to the wholly evil will as is possible. He had gone the way of all tyrants: beginning well, at least on the level that while desiring to order all things according to his own wisdom he still at first considered the (economic) well-being of other inhabitants of the Earth. But he went further than human tyrants in pride and the lust for domination

As a result he chose to make Boromir an object lesson of the impact of the Ring and its power.