It’s revealing that politicians who oppose the bill tend to deny the medical evidence that the 20-week-old fetus can feel pain. What they don’t deny is the underlying premise: that if the fetus does endure excruciating suffering in the act of being killed, it should be protected by law. These politicians no doubt tacitly accept this premise because they have to answer to constituents who might not take kindly to expressions of outright moral indifference to suffering.

That’s a real sign of vulnerability for the absolute pro-choice position, which is no doubt one reason why more and more advocates of that position have been staking out increasingly extreme views that do deny the premise — proclaiming the termination of a pregnancy at any stage to be a matter not just of moral indifference but actually a positive good for which no woman should ever feel the least bit of guilt or even ambivalence.

That an activist would operate this way — strong-arming senators to champion views that harmonize with a mere 14 percent of the country — isn’t surprising. Planned Parenthood, Emily’s List, and their opinion-journalist allies are acting precisely like the NRA and its champions on the right, warning receptive politicians ominously, “Give an inch and the enemy will take more than a mile next time! No compromise allowed!” And so we get no restrictions on late-term abortion, just as we get no serious federal gun control.