FREDERIC J. BROWN via Getty Images The U.S. is woefully behind the rest of the world on its leave policies. Hillary Clinton is one of the presidential contenders who wants to change that.

For the first time ever in a presidential race, candidates are actually publicly debating paid maternity, paternity and family leave.

On Thursday, Hillary Clinton unveiled her plan on family leave, which would give working parents 12 weeks off after the arrival of a new baby or to take care of a sick or injured relative. Bernie Sanders is floating a similar proposal, and is expected to offer more details in a news conference Friday. On the GOP side, Marco Rubio has suggested giving businesses tax credits for offering leave; the other Republicans don't support any kind of national policy.

Contrast the current state of affairs with 2008. Back then, though both Clinton and Obama said they favored family leave, there was no public debate or discussion on the issue, Heather Boushey, an economist and president of the Center for Equitable Growth, who has advised Clinton, told The Huffington Post by email.

"This kind of debate has not happened before -- in such detail -- at the national level. I think that the fact that the Democrats are debating not whether, but how, to do this indicates that this will likely stay on the agenda through the general election," Boushey said.

The difference between Sanders and Clinton's plans is in the way they fund the leave, as HuffPost's Jonathan Cohn explains. Sanders would fund leave through a small payroll tax -- .4 percent shared by employee/employer -- via a bill called the Family Act that's already floating around Congress. Clinton is saying she'd pay for her leave proposal with a new tax on the wealthy.

Though Clinton has always supported paid leave -- and her husband signed the current unpaid family leave law in 1993 -- she hadn't aggressively stumped for it until 2015, as The New Republic recently noted.

As recently as June 2014, Clinton said that pursuing paid leave wasn't politically expedient, though it should ultimately happen.

“I think, eventually, it should be [implemented],” Clinton said on CNN during her book tour. However, she qualified her support by saying Congress wouldn't pass such a law: “I don’t think, politically, we could get it now.”

A lot has changed in the past year. On the corporate side, companies like Amazon, Netflix and Facebook have been falling over themselves improving their paid leave plans.

In terms of policy, all the action's been at the state and local level. Several states and cities are considering plans, in part because the Department of Labor is offering grants to interested policymakers who want to study the idea.

New York state, D.C. and Connecticut are all expected to pass laws this year, Ellen Bravo, the director of Family Values @ Work, a nonprofit coalition of groups pushing for paid parental and sick leave in the U.S., told HuffPost. New Jersey, California and Rhode Island already offer paid leave.

Andrew Burton via Getty Images Bernie Sanders wants to fund leave through a payroll tax.

Bravo and Boushey both emphasized what a game changer a policy like this could be for working families in the U.S., many of whom risk financial devastation when a family member falls ill or there's an unforeseen complication during childbirth. Only 13 percent of workers in the U.S. have access to paid leave; the percentage is even lower for those with low incomes.

"Over and over, people talk about this terrible thing that happened that was unpredictable," Bravo said. "'I didn't know my baby was gonna come early; I didn't know my dad was going to have a stroke.'" Events like those shouldn't be the equivalent of financial disaster, she said.

The U.S. lags behind the entire globe when it comes to paid maternity leave. We're the only developed country without some kind of paid leave policy, and one of only a handful of countries globally that offers nothing to new parents -- in company with Papua New Guinea.