Mark Kirk and Eliot Engel want to make the current cruel, pointless sanctions on Iran even more cruel:

On the contrary, we are convinced that taking immediate steps to increase the pain of sanctions is the only way to persuade the Iranian leadership to change course.

Like all Iran sanctions supporters, Kirk and Engel believe that the Iranian government will eventually change its behavior on the nuclear issue provided that Iranians suffer sufficient pain. It doesn’t seem to matter to them that there have been no changes in regime behavior after years of existing sanctions. Instead of facing up to the reality that sanctions on Iran have completely failed in achieving their stated goal, they demand that the U.S. intensify these fruitless punitive measures. Piling on more sanctions is the standard hawkish answer to the ongoing futility of existing sanctions.

If even harsher sanctions brought Iran to “the verge of economic collapse,” as Kirk and Engel hope, what do we think the Iranian response is likely to be? Any self-respecting government is not likely to become more cooperative on a major issue when its country’s economy is ruined by the actions of foreign powers. It is much more likely to remain defiant. Kirk and Engel assume that harsher sanctions will compel Iran to comply with U.S. demands on its nuclear program, but an even harsher sanctions regime might understandably lead Iranian leaders to conclude that the U.S. is so unremittingly hostile to their government that no deal is possible.

Kirk and Engel say that they aren’t calling for an end to diplomacy, but the passage of more severe sanctions will surely sabotage future negotiations, so it amounts to much the same thing. The flaw in all of this is that Iran hawks want to force Iran to do something (“suspending all enrichment-related and reprocessing activities”) that it is probably never going to do. That will only lead to increasing tensions and possibly armed conflict.