'Why the US is hesitant to take on Iran?'

It is obvious that the lessons learnt from the recent past do not provide for US the much needed directions, and as the writer has already pointed out, that Iraq is not Iran. Iran unlike Iraq will retaliate if an attack is made on its nuclear sites. What possibly Iran can or will do to counter the much feared retaliation is being seriously calculated by CIA experts. The answers are vague or not there at all, so more time is needed for the move.

Moreover the calculation which is at hand is the requirement of 150,000 US troops now in Iraq for action in Iran. To tackle the declaration of global war against terrorism US is already confronted with the high escalating cost of men and material, as well over fifty percent of the federal budget is allocated for defence from terrorism. Should the defence spending be further geared up so as to meet the requirement of men and material to invade Iran? The answer to that question needs more time, of course.