good evening, everyone. i m erin burnett. it is an absolutely gorgeous night here in the high desert. high stakes in the high desert, because we are live in mesa, arizona. in just one hour, the candidates will face off in what could be the everyone hear that bird? i m sure you hear it too. must be excited to go outfront. well, it has been a bruising and surprising primary season, and it s going to be a really big debate tonight. what a difference from the last time these men shared a stage. take a look at january. just before mitt romney s landslide victory in florida. he was riding high, but tonight, a very, very different story. a lot has changed and the former massachusetts governor knows it. he is feeling the heat from rick santorum, who surge shows absolutely no sign of abating right now. he won, colorado, minnesota, and missouri. and just today, another national poll shows him leading mitt romney 35 to 26%. in the two states voting on tuesday, arizona and michigan,