There is no “easy button” to press to redraw congressional and legislative election districts in a year that could prove especially hard since the federal government doesn’t promise to deliver the census data needed to start the process until a month after Iowa law says lawmakers must finish it.Iowa this year must redraw boundaries for its four congressional districts and 150 legislative districts to reflect population changes since the last census in 2010.The standards for doing that are strict, Ed Cook, senior legal counsel for the nonpartisan Legislative Services Agency told four members of the Temporary Redistricting Advisory Committee on Monday.Unlike in other states accused of gerrymandering, the process in Iowa requires the new districts be created with the smallest possible population variance between them as possible.