As the guard prepares to change in a week, Treasury Secretary Jacob Lew said in an exit memo released last week that only legislation can comprehensively address “the ongoing shortcomings of the housing finance system.” In the memo, Lew documents the Treasury’s progress over the last eight years and outlines his goals for the future of the department. He said that fixing the housing finance system remains the major unfinished piece of work of post-financial crisis reform. While he said the housing market has improved, Lew acknowledged that many homeowners and neighborhoods continue to struggle. “A starting point for such legislation should be the principles President Obama laid out in 2013, which stressed a clearly-defined role for the...