ISIS: U.S. vs. Iran and an Iraq that does not care

Iranians have abandoned their secretive military operations and bombed Iraq openly.  they used 1970s jet-planes.  They are not openly saying that they are allies with the U.S. but rather they are expanding their shiite influence into the sunni dominated iraq. Different areas of the middle east show their support for Iran's military operations.  The U.S. worries that Iran's  Shiite military involvment will deepen sectarian divisions, and make themselves unappealing to Sunnie Iraqi's in the region.  Iraqi leaders have often been faster to help with the fighting than the U.S. operations.  In the same way they view Iranian forces that did not step into the fight against ISIS or ISIL when they attacked Baghdad.  Iranians see Obama's letter as weak and if they would have written a letter of the same fashion to them to tell them of their caution to intervene with the ISIS conflict, they would have deemed themselves weak too. http://www.nytimes.com/2014/12/04/world/middleeast/iran-airstrikes-hit-islamic-state-in-iraq.html?_r=0