Caleb Orr, a policy adviser for Rubio, explained the distinction between the two bills by noting that requiring a set period of leave in order to obtain the benefit — as the Lee-Ernst bill would do — might discourage at least some families or parents from choosing to take leave at all, which would undermine the goal of the policy.

“The main practical fact that we encounter in requiring leave is that most low-income mothers don’t work salaried professions,” Orr said. “Requiring leave in a one-month to three-month fashion in a standardized way simply does not match with the reality of low-wage work forces.” He argued that the Rubio-Romney bill would benefit small-business employees not eligible even for unpaid leave under the Family and Medical Leave Act of 1993, as well as those who might work part-time or work from home shortly after the birth of a newborn.

Meanwhile, Jena McNeill and Christy Woodruff, advisers in the offices of Ernst and Lee respectively, emphasized the importance of facilitating time for new parents to bond with and care for a newborn, which wouldn’t necessarily happen without the requirement that parents actually take time off work in order to receive the benefit.