Thursday, the Democrats not only looked a gift horse in the mouth, they gave it back, too. The gift? An up-or-down vote on single-payer health insurance, under which the federal government would provide health insurance for all Americans and covering the more than 20 million Americans still uninsured under the Affordable Care Act. Not a single member of the Democratic caucus supported it. This seems so obviously a mistake that it bears to ask the question: Why didn’t they vote for it? The short answer is, congressional Democrats are afraid.

This past week an unexpected champion took up the cause of single-payer health insurance: Republican senator Steve Daines of Montana. His amendment to the Republican health care plan would replace the bill and cover all Americans. It was plainly a tactic to get Democrats on the record in support of single payer. The Democrats didn’t go for it; 43 members of the Democratic caucus voted “present” and five members voted “no.”

Until now, the Democratic Party has been largely occupied with pushing back against the Trump administration’s agenda: seeking to block unqualified and ultra-right judicial nominees, insisting on investigations into Trump’s collusion with Russia, mobilizing against efforts to repeal the Affordable Care Act. This has been somewhat successful on a policy level, as the administration has yet to achieve a single significant victory in Congress. But in terms of politics, it is not enough for Democrats to be the not-Republicans — a lesson learned in 2004 and again in 2016. The Democrats must not only propose an affirmative agenda, something toward which they recently took steps, but show they are willing to fight for it. The single-payer amendment presented an opportunity to do that by showing leadership and mettle.

We elect people we trust to lead us, not to blindly follow popular opinion. It is no surprise, then, that the endorsement of prominent politicians can actually increase support for policy. Marriage equality provides a good example. Prior to Obama’s announcement in May 2012 of his support for same-sex marriage, only a handful of politicians on the national stage had done so. At that point, support stood at a bare 50 percent in favor, and had only recently emerged from the mid- to low-forties. Within months, support jumped to 53 percent and by a year later it had climbed to the high fifties. Though this is not conclusive alone, it stands to reason that as more and more national politicians—nearly the entire Democratic caucus in both the House and Senate—announced and explained their support, they convinced their constituents of the policy’s legitimacy.

We can see the beginnings of this with single-payer health insurance. In March 2014, a mere 21 percent of Americans supported single-payer health insurance, and only 47 percent said the government has a responsibility to make sure all Americans have health insurance coverage. After Bernie Sanders made this one of his key issues in his 2016 presidential run, it grew to 28 percent support for single-payer in January of this year, and then 33 percent as of a month ago. Support is particularly strong, nearly half, among millennials, regardless of party affiliation. Likewise, around 60 percent of Americans now believe that it is the government’s responsibility to ensure that all Americans are covered by health insurance. Democrats should have seized on the chance to make this an issue, going out and working with progressive groups to convince Americans to finally insure all of us, rather than running scared

Skeptics might note that support for single-payer is currently substantially lower than support for marriage equality was, the stakes are likewise far lower: this is merely an amendment in the midst of an extremely complex health care debate, with the mid-term election over a year away. These conditions actually make support for the amendment more valuable, not less. Given the effects of national politicians endorsing policy and seeking to convince their constituents, support for single-payer could grow substantially over the next 16 months.

Moreover, though unlikely, it could have passed. Cynics might scoff, but historical precedent demonstrates the possibility. Originally, the Civil Rights Act of 1964 did not prohibit sex discrimination. That change was due to the effort of segregationist Southerners who sought to delay the vote on the Act and fracture the fragile coalition seeking to pass the bill. Many proponents of the Civil Rights Act opposed the amendment, concerned that it would doom the legislation—but it passed regardless. Ironically, many of the “yea” votes were Southern Democrats who believed it would sink the law entirely. When the dust settled, women suddenly found themselves, at last, protected by federal anti-discrimination legislation.

Though the facts are not precisely parallel now, the miscalculation by segregationists shows that a simple amendment—the sex amendment was a one-word addition to the bill—designed to implode a more moderate effort, or to embarrass those who support it, can change history. The same could have happened here, if only the Democrats had gathered their courage.

Finally, Americans deserve to know where their representatives stand on single-payer health insurance. A majority of Democrats—52 percent—now support single-payer health care, and it is a priority for many of us. If we are supposed to make educated decisions in the voting booth, if we want to send representatives to Washington who share our values, the fact that congressional Democrats are so shy to discuss, let alone vote, on single-payer militates against our ability to do just that. It is disingenuous at its very best.

As Democrats, we need to get our act together. It is not enough to reveal the Trump administration to be an omnishambles populated by cretins; we must go further. We must present an agenda that speaks to the problems they face daily; whether the administration has colluded with Russia is of no import to a family worrying about how to afford their medical bills. It is time to say: 22 million uninsured Americans is 22 million too many. Campaign on that. Vote on that. The moment for milquetoast liberalism is over.