Casey Jr. could run for President in 2020 (or 2024 if a Republican wins).
And as IceSpear said, the Dems are intolerant of anyone that disagrees with them on their litmus tests.
Oh, so, like the Reps?
Nah.
Democrats have Joe Manchin and Heidi Heitkamp in their caucus. Meanwhile, people like Pat Roberts and Thad Cochran are facing primaries for being "too moderate". Enough said.
And Dems haven't complained about Manchin? And a major reason why people like Roberts and Cochran are getting challenges is because they have been around for awhile. Limited time in office is obviously a strong point within the GOP.
Whatever the case, the point here is that the conversation these days is almost entirely on the GOP being a litmus test party when the Dems are a far bigger culprit on the issue of abortion. I'm definitely willing to bet a Pro Choicer like Sandoval ends up on a national ticket before someone that's Pro Life ends up on the Dem ticket.