We’re Not Invading Iran

Taking the military option off of the table would render diplomacy worthless and meaningless.

Without a military option, diplomacy with Iran is just so much bribery, and there is nothing we can offer, short of self-immolation (taking Israel with us), that will satisfy Iran. If there is no threat of military action, then there is no chance (not a small chance, but absolutely no chance, zero, zip, zilch, nada, nyet, la, non, et cetera) of a diplomatic success.

Granted, I don't think diplomacy has any chance as it is, but there is no chance if there is no military option. The best hope to avoid war is the Ledeen option: empowering the locals and assist internal regime change (with a different regime, say one similar to India, I wouldn't care if Iran had nukes). Note the word there, hope; foreign policy doesn't permit hope.