WASHINGTON--First Lady Michelle Obama, who never went up to Capitol Hill to lobby for the school lunch bill, on Monday penned an op ed in the Washington Post urging lawmakers to reauthorize the measure that would help kids deal with obesity, her signature issue.

Mrs. Obama has spoken out for the past year on the need for the legislation. Both the House and the Senate passed versions of the bill, but the two chambers have to reconcile their different versions. With Congress taking most of August off, and then faced with November elections, there are concerns the final work on the bill-which is not particularly controversial--will not get done.