Is the US Yielding to Iran's Preconditions for Negotiations?

It couldn't be worse timing, but Dennis Ross, the US envoy to Iran, is being reassigned.

People don't know exactly why Ross is being ousted. It might be because he was thought to be too hawkish, or too pro-Israel, or simply because Iran didn't want to accept Ross as an envoy because he is a Jew.

Early in the last Presidential campaign Barack Obama said that we should meet with Iran without preconditions (a position that he later "nuanced"). Who thought then that it might be Iran that would have the preconditions? And who thought that we might be the ones submitting to them?