Sen. Bill Cassidy, R-La., speaks during a forum on healthcare during the Southern Republican Leadership Conference Saturday, Jan. 19, 2019, at the Pontchartrain Convention and Civic Center in Kenner.

U.S. Sen. Bill Cassidy has been looking to take a lead on some sort of paid family leave bill for a while now, but he hasn’t outlined just what he’d support.

This week, he did add a significant “who” to the equation. Cassidy, a Republican up for reelection in 2020, told a gathering at the American Enterprise Institute that he’s lined up a Democratic partner, newly elected Arizona U.S. Sen. Kyrsten Sinema.

The significance of the new partnership is that, while support for paid family leave is gaining traction, leaders in Washington appear starkly divided by party.

Two bills introduced by fellow Republican senators call for workers who take paid leave to essentially tap into their future Social Security benefits, agreeing to delay collecting them on the back end. Many Democrats consider that a non-starter, something that would penalize the people who take leave, making it really not a benefit at all. The favored model on the left involves a small payroll tax that would be shared by employees and employers.

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Another huge question is whether leave would be available to anyone caring for an ailing relative, or only to new parents caring for a child. Cassidy has said that he leans in the latter direction because “that seems to be where the greatest need” is, he said in a conference call with reporters earlier this week. Many people working on the issue believe any new benefit should be more broadly available.

Cassidy did say he’s striving to view the issue through the lens of lower-income workers, who are less likely to have paid leave benefits through their companies and face different — and more immediate — cash flow challenges than better-compensated workers.

Asked this week whether he was ready to offer a preview of his proposal, Cassidy said that “we’re keeping our powder dry, because we want to form a little bit of a broader coalition.”

Cassidy and Sinema are the first senators to formally join forces across the aisle on this issue. That, at least, is a good start.

Follow Stephanie Grace on Twitter, @stephgracela.