Any deal that allows Tehran to retain centrifuges for uranium enrichment will encourage a nuclear-armed Iran and proliferation throughout the Middle East.
Read more on Washington Post: http://www.washingtonpost.com/opinions/iran-deal-could-encourage-rather-than-limit-nuclear-activity/2014/02/28/74cc36ee-9d71-11e3-9ba6-800d1192d08b_story.html