The problem is that Sanders’s vision — and the vision of Perez and the DNC — as they laid it out this week, looked less like a radical transformation of the Democratic Party and more like a return to mistakes the party has made in the past. These mistakes have nothing to do with economic equality, and everything to do with a willingness to sacrifice the rights of much of the party’s base.

Sanders is wrong that reproductive rights (or gay rights, for that matter) are separate from economic issues. The ability to control reproduction is central to women’s social, professional, and economic stability, and the women most likely to require abortion services and to be negatively affected by restrictions on access to reproductive health care are poor and low-income women, disproportionately women of color.

But he and Perez were also wrong to view compromising on abortion as part of a pragmatic political path forward and to hold up an aggressively anti-abortion Democrat as some exemplar of progressivism’s future. Heaps of contemporary polling shows abortion is not the divisive issue it was long assumed to be. In 2015, polls showed that seven in ten voters, including independents — and even in Kansas­ — not only supported safe and accessible abortion but were willing to vote based on that support. A postelection Pew study found support for Roe to be at 69 percent, an all-time high. Omaha, the city where Heath Mello is running for mayor, was carried by Clinton — who made the most full-throated case for reproductive rights ever offered by a presidential candidate in her final debate against Donald Trump — by eight points. (For the record, Mello released a statement on Thursday claiming that, “While my faith guides my personal views, as Mayor I would never do anything to restrict access to reproductive health care,” which is a lovely sentiment, except for the fact that as state senator he literally did do lots to restrict access to reproductive health care.)

There is absolutely no need to abandon women’s rights in the name of advancing progressive politics. And yet the party has done it time and again, often after losing presidential elections.