WASHINGTON, March 7 (Reuters) - President Barack Obama's abrupt shift to a schmooze offensive - dining and visiting with Republican lawmakers - reflects a need for some resolution in the budget wars so he can move on to other priorities like gun control and immigration that could define his second term. A drop in his approval ratings in recent weeks and a new round of media questions about his scant socializing with members of Congress have also likely put pressure on Obama to start talking to his political foes. "He has a limited amount of time to tackle the items on his agenda, like immigration, increasing the minimum wage and gun control," said Nancy-Ann DeParle, who recently stepped down as deputy White House chief of staff and is now a Brookings Institution guest scholar. "He can't waste time on a protracted battle over the budget and sequester," said DeParle. "That should be left to the Congress to figure out." With another budget deadline looming, he needs to get a deal completed so he can seek legislative approval of other items on his second-term agenda.