A solid foundation on which to build a nuclear accord with Iran

THE preparatory agreement between Iran and the United States and other major powers that was issued on Thursday in Lausanne, Switzerland, providing for the "key parameters" for a final accord on Iran's nuclear programme may not be perfect, but it is the least-worst option to ensuring that the Islamic Republic will not be a nuclear threat.

The deal is not yet finalised, and it remains a bit sketchy. Negotiators will be working to try to come up with a comprehensive…