One does not simply walk into Mordor. Its Black Gates are guarded by more than just Orcs. There is evil there that does not sleep, and the Great Eye is ever-watchful. It is a barren wasteland, riddled with fire and ash and dust. The very air you breathe is a poisonous fume. Not with 10,000 Men could you do this. It is folly.
Boromir, who feels his people should wield the Ring, speaks to the council.