There was at least one conspicuously missing issue in Houston. Photo: Robyn Beck/AFP/Getty Images

The moderators and candidates covered a lot of ground in last night’s third-round Democratic debate in Houston, including some that had not been very adequately discussed in the past, like trade policy. But one very important issue to Democratic voters never came up, as Anna North pointed out:

Abortion rights are shaping up to be a key issue for Democratic voters going into 2020.

But you wouldn’t know it from the third Democratic debate on Thursday night.

The moderators didn’t ask a single question about abortion or reproductive health more generally, and candidates didn’t bring it up.

Nor did the closely related topic of judicial appointments — a key responsibility for any president — come up either. And as North notes, it’s a topic the Democratic rank and file appears to care about passionately:

In a poll earlier this year, 79 percent of likely in-person Iowa Democratic caucus-goers picked support for abortion rights as a must-have for a candidate — more than any other issue.

And a lot is at stake. Near-total bans on abortion have swept the country this year, and while they’re tied up in the courts, they could one day reach the Supreme Court — where the next president will very likely get to make at least one appointment.

The subject was discussed in one of the two July debates, and perhaps the outcome explains why it dropped off the debate agenda: Kamala Harris pushed Joe Biden to explain his reversal of an old position supporting the Hyde Amendment that prohibits use of federal funds to pay for abortion services. Biden justified it as a by-product of his comprehensive health-care-coverage plan, which made excluding such services arbitrary and unfair. With that, it was clear that the last big substantive abortion-related issue dividing the Democratic field had basically vanished — and in Houston, the whole topic vanished, too. It may have contributed to this occlusion that aside from Biden, the candidates with a history of opposing abortion rights at some point in the past (e.g., Tim Ryan and Tulsi Gabbard) had dropped off the debate stage.

For those most concerned about the fragile nature of reproductive rights, though, dropping the subject because it is no longer a source of intraparty conflict (at least in the presidential nomination contest) is dangerous. It encourages complacency, a lost opportunity to mobilize voters against the Republican threat to choice, and for the next Democratic administration, perhaps a lower priority for efforts to protect and improve medical services critical to women.

This perspective, of course, is alien to TV-network debate moderators who want conflict and drama, and to journalists and undecided voters who want to understand policy areas where candidates differ. Still, worried pro-choicers had to wonder why there was plenty of time in Houston for a half-hour of redundant moderator-driven wrangling over the cost and consequences of Medicare for All, but nothing about abortion and the courts.

Perhaps it’s useful to see how this played out in the Republican nominating contest of 2016, where — against the background of growing party unanimity in supporting the reversal of Roe v. Wade and, short of that, any abortion restriction the courts would allow — there were legitimate doubts about where the front-runner stood. Relatively late in the primaries, Benjamin Wallace-Wells observed that of all the things Donald Trump’s rivals were attacking him on, criticism of his hazy and often clumsy statements on abortion wasn’t very prominent, particularly in debates:

At the last Republican Presidential debate, in Miami, on March 10th, no one used the word “abortion.” The topic wasn’t raised at the previous one, in Detroit, either. When abortion has come up at the Republican debates in recent months, it has usually been mentioned briefly, often in the context of the Supreme Court vacancy. A generation of conservative politicians — the George W. Bush generation, more or less — had developed a whole gruesome lexicon for describing various types of abortion. Ted Cruz gestured at that heritage when he described Donald Trump as a supporter of “partial-birth abortion” in ads and during a debate in Greenville, South Carolina. But the specific challenge went unanswered — Trump responded by calling Cruz a “nasty guy” — and the general matter of abortion, too, seemed to fade from the Republican contest.

Wallace-Wells was so struck by this phenomenon that he suggested the era of conservative culture wars may have been coming to an end. That now sounds naïve, but it is true that Trump’s reliance on the abortion issue to woo conservative Evangelical and traditionalist Catholic voters to his banner mostly took place during the general-election campaign. His really crucial step, later thought to have been instrumental in mobilizing white Evangelical support, took place at the final October 16 debate with Hillary Clinton, as the Washington Post reported in its transcript, when moderator Chris Wallace asked the key question:

WALLACE: [W]hat I’m asking you, sir, is, do you want to see the court overturn — you just said you want to see the court protect the Second Amendment. Do you want to see the court overturn Roe v. Wade?

TRUMP: Well, if we put another two or perhaps three justices on, that’s really what’s going to be — that will happen. And that’ll happen automatically, in my opinion, because I am putting pro-life justices on the court. I will say this: It will go back to the states, and the states will then make a determination.

Thus Trump eschewed the ancient model of refusing to adopt “litmus tests” for SCOTUS nominees, and just flat-out promised the anti-abortion movement what it most wanted. That he kept this one promise by outsourcing his judicial vetting process to the Federalist Society and the Heritage Foundation — hotbeds of hostility to reproductive rights — sealed his bond with the Christian right, encouraged the recent riot of patently unconstitutional state abortion laws, and justifiably convinced pro-choice Americans that the 2020 elections would reflect a definitive fork in the road.

Now, 2020 presidential candidates don’t have to be explicitly asked about abortion or court appointments to find ways to make it clear that they understand that this should become a crucial voting issue for Democrats, as it has already become for Republicans. But more importantly, when the general-election campaign arrives, they need to be prepared to emulate Trump in leaving nothing to the imagination about their own intentions, and leaving no pro-choice voter with illusions that the outcome won’t matter.