good evening, everyone, i m erin burnett. outfront tonight, a shady red line. a red line the whole world is watching. the red line is the line that the obama administration and members of congress say iran cannot cross. listen to this. always keep all of our capabilities ready in the event that those red lines are crossed. that signaled an intention by iran to cross what we call the red line. the fact that they are active here has crossed a red line. the problem is, when someone tells you there s a red line you can t cross, or else? two things matter where exactly is the line. and what exactly will happen to you if you cross it. defense secretary panetta has stated the obvious getting a nuclear weapon crosses the line. and today an obama administration official who would only discuss this sensitive issue anonymously got a little more specific, telling cnn s security blog that iran moved toward 90% uranium enrichment, the level required for a weapon, is potent