today on inside politics, together again. barack obama and joe biden are teaming up to promote one of their biggest accomplishments. we have details on their rare white house reunion and whether the former president can help the current one get reelected. plus a growing divide. the u.s. and israel are no longer in lock step on how to prosecute the war against hamas terrorists. as a top biden official meets with the leader of the palestinian authority in the west bank. republican candidates have one month left to make their case to iowa voters. nikki haley just agreed that the cnn debate stage will be one of her final stops. i m dana bash. let s go behind the headlines and inside politics. we start with obama and biden joining forces again. the former president taped a new ad with his former vp on the importance of obamacare. cnn s kevin liptack is at the white house. you broke this story. tell us about this. reporter: it s always interesting to see how this white ho