No incoming president has set a more ambitious work-family agenda than Barack Obama. The president-elect has said he wants a federal sick-day mandate and expansion of family leave. With Democrats also in control now of legislatures in 27 states, up from 23 before the election, change on this front is likely.

But such proposals face historic obstacles, in the form of a cratering economy and paralyzing state deficits. Thus new entitlements are likely to move ahead unevenly, if at all. While the politicians do battle, it will...