Overnight, he will transform from everyone’s favorite political uncle into the personification of the glass ceiling. Furious Hillary Clinton supporters will hold up Biden as the latest example of a man refusing to let a qualified woman reach the top.

Why would Biden suffer that sexist distinction when rival candidate Sen. Bernie Sanders has not? Because Sanders has clear-cut substantive differences with Clinton: from socializing health insurance to capping the size of banks to the Patriot Act to the Iraq War vote.

Simply put, Sanders has a reason to oppose Clinton, just as the Iraq vote provided the basis for Barack Obama to leapfrog over his elder. You can’t plausibly argue the Sanders candidacy is an exercise in mansplaining.

Biden, on the other hand, is cut from the same Establishment Democrat cloth as Clinton. They have taken similar votes that Democratic base voters view as cynical, including in favor of the Iraq War resolution, the Patriot Act and the 2001 bankruptcy bill. They both eschew left-wing pipe dreams like single-payer health insurance. Perhaps some daylight would creep between them over the course of a presidential campaign, but it would not amount to a deep philosophical breach. A Clinton presidency would be similar to a Biden presidency.

In turn, there’s no reason for Biden to oppose Clinton, at least, not an ideological one.