Just in case you aren't a nuclear physicist, 3%-5% purity is all the enrichment (refinement) of uranium-235 one needs to run a nuclear power plant. 90% purity is what you'd need to build a high-yield, compact modern nuke Technically, anything over 6% purity works well enough for a large, crude, "dirty" bomb -- you just need more mass with less purity. But the enrichment process that purifies uranium up to 20% is most of the work needed to get to 90%. Once you have the capability of refining uranium to the 20% mark (highly enriched uranium or HEU), you just keep refining it over and over.
Tomorrow, Iran begins enriching uranium to 20%.
If Iran is not stopped, they could have enough 90% enriched uranium to build a nuclear weapon by the end of summer -- that is, if this isn't all a sleight-of-hand trick to cover for Iran's obtaining weapons-grade uranium or functional weapons from North Korea, Pakistan, Russia or China. Iranian leaders keep forewarning the world that they will "punch the arrogance (of Western powers) ... in a way that will leave them stunned" on 11 February -- only three days away. Iran used to be Persia, after all -- the country where chess was likely invented. Whether the Iranians are making their own (and are willing to settle for a lower level of enrichment) or buying uranium, we might not have to wait long to see one of the following:
1. A nuclear explosion in either the Dasht-e Kavir or Dasht-e Lut desert
The former would be a claim to dominance over the entire Middle East, sparking off a more open and frantic nuclear arms race with Egypt, Turkey and Saudi Arabia among others. Egypt's President Hosni Mubarak told an Arab summit almost a year ago, in March 2009, "A nuclear armed Iran with hegemonic ambitions is the greatest threat to Arab nations today." One can exchange the word "Arab" for "all" and the statement is still true.
The latter result of Iran's enrichment process would very likely be the opening salvo of a devastating nuclear war. In chess terms: the first puts us all in check, the second, checkmate.
How much longer will we play around with sanctions and stern finger-wagging while Iran marches toward the end of the world?