The goal of U.S. trade embargo and economic sanctions programs is to change behavior and topple regimes. They are designed to toggle on and off as circumstances warrant, allowing them to serve as flexible tools of a foreign policy coined by Reagan’s Secretary of State George P. Schultz as “Light Switch Diplomacy.”  In effective sanctions programs, the eventual question invariably comes to when to flip the switch “off” – a question very much at issue in criticisms of the Obama Administration’s current Iran sanctions policy.
The Iran sanctions program is by far the largest and most complicated active U.S. sanctions program. Its primary goal is to stop Iran’s nuclear weapon development activities. It is also aimed at curbing Iran’s support of international terrorism and Iran’s atrocious human rights record.
Last month, the Obama Administration agreed to an interim deal with Iran in which the U.S. will suspend a very limited scope of the sanctions program in return for Iran’s agreement to cease certain nuclear weapon development activities.
Prior to the interim deal, the administration took the position that Iran does not have an inherent right to enrich Uranium. This is consistent with current United Nations Resolutions prohibiting Uranium enrichment activities by Iran and follows a limited reading of Article Four of the Treaty on Nonproliferation of Nuclear Weapons.  It is also consistent with U.S. regional stability and antiterrorism policies, which both aim to prevent Iran from possessing a nuclear weapon. Nevertheless, the interim deal allows Iran to maintain Uranium enrichment capabilities for use in peaceful nuclear energy activities and arguably establishes this concession as a baseline in any further negotiations leading to a permanent agreement. 
Many U.S. allies view allowing Iran to continue enriching Uranium as a major deviation from the primary goal of the sanctions. As noted by Israeli Prime Minister Benjamin Netanyahu:
“For years the international community has demanded that Iran cease all uranium enrichment. Now, for the first time, the international community has formally consented that Iran continue its enrichment of uranium.” 
Underlying this concern of Israel and other allies is that permitting Iran to continue enrichment activities, at any level, will eventually result in “breakout capacity,” enabling Iran to make a quick dash to weapons grade Uranium.
* * *
 George P. Schultz, “Light-Switch Diplomacy,” Business Week, May 18, 1979, pp. 24-26.
 Article IV to the Treaty on Nonproliferation of Nuclear Weapons (“Nothing in this Treaty shall be interpreted as affecting the inalienable right of all the Parties to the Treaty to develop research, production and use of nuclear energy for peaceful purposes without discrimination and in conformity with Articles I and II of this Treaty.”).
 See Joint Plan of Action, Geneva, November 24, 2013, the preamble of which provides, “This comprehensive solution would involve a mutually defined enrichment programme with practical limits and transparency measures to ensure the peaceful nature of the programme.” The deal further provides that the final step of a comprehensive solution will “[i]nvolve a mutually defined enrichment programme with mutually agreed parameters consistent with practical needs, with agreed limits on scope and level of enrichment activities, capacity, where it is carried out, and stocks of enriched uranium, for a period to be agreed upon.” These provisions, as well as Iran’s agreement not enrich Uranium over 5% for the duration of the interim deal, reasonably imply that enrichment activities below that level will be acceptable to the parties in the future.
 Statement of Israeli Prime Minister Benjamin Netanyahu, State of Israel Prime Minister’s Office, available at http://www.youtube.com/watch?v=9gZjPKiMWRM