Preconditions can damage a country’s negotiating position.  No country is likely to agree to conditions that will significantly reduce its bargaining power once it gets to the table. It would be diplomatically foolish to agree to preconditions that would essentially be the subject of the negotiations and the reason why the negotiations were needed in the fist place [1] . If North Korea agreed to freeze development of its nuclear arsenal, or if Iran agreed to stop its nuclear enrichment programme, once the meeting between the two leaders took place, the position from which they started negotiating would be significantly weaker than the US’s.  [1] Klein, Rick. “Obama’s Evolving Take on Meeting with Iran.” ABC News. 20 May 2008.