Remember that much-maligned line first uttered by Condi Rice when the Bushies were bamboozling congress and the American people into war in Iraq: "We don't want the smoking gun to be a mushroom cloud?"
It turned out--as we now know to our everlasting regret--that Saddam had no WMD, and her cute turn of phrase, while mighty scary, was empty at its core.
This time, though, it's for real. It's now Barack Obama's unenviable job to convince an incredulous public that the old Domino Theory is still valid. If Afghanistan falls to the Taliban and al-Qaida is allowed to thrive there, the infection will spread even deeper into an already rickety Pakistan, and possibly overwhelm its government.
Normally, we'd just allow the warlords and nut jobs in that part of the world to cancel each other out, but we're talking upwards of 80 nuclear weapons here, any one of which in the wrong hands could mean disaster.
Obama's speech will have to be short, sweet and to the point: no "nation-building," no "nurturing democracy," no subtlety. If he's going to sell this thing, we have to come away thinking, "Either we commit, or someday we're all going up in a ball of flame."
Americans aren't good with abstract concepts (think, "deficit spending"). They do, however, understand matters of life and death.