Feeling the Kaine. Photo: Alex Wong/Getty Images

The Affordable Care Act has brought America’s uninsured rate to a record low 8.6 percent. And if a bunch of Republican governors weren’t convinced that giving poor people health-care access is the first step on the road to serfdom, that figure would be even lower. Meanwhile, in 2015, national health-care costs grew at their lowest rate in nearly two decades.

Still, Obamacare’s Rube Goldberg approach to universal health care has produced no small number of problems. Many of the marketplaces have proven to be a rotten deal for for-profit insurers: Turns out people willing to go through the hassle of securing health insurance through the exchanges are sicker than the general population. And while this problem was supposed to be mitigated by the individual mandate — which levels a punitive tax on young, healthy people who chose to forgo coverage — unemployed millennials have opted to pay the penalty and carry on believing that they are immortal.

This has led some insurance giants to scale back their participation in the program and/or hike up premiums to compensate for the costs of maintaining a sicker clientele. Now, in roughly a quarter of U.S. counties, there is just one private insurer offering coverage in the local “marketplace.” This absence of competition isn’t helping to counter the growth of premiums and deductibles.

There are a couple of ways to go about solving this problem. One would be to make the mandate radically more draconian: To get its public-private approach to universal health care to work, Switzerland threatens those who refuse to buy insurance with jail time. Or we could pull a Bernie Sanders and go full socialism in the health-care sector.

But the most politically realistic short-term fix — which President Obama and Hillary Clinton have both signed on to — would be to add a public option. Which is to say, let a public insurance program modeled on Medicare compete against private insurers in the exchanges. Such a program would set a minimum standard for quality of coverage, ensure competition, and use the government’s bargaining power to reduce payouts to drugmakers, medical-device manufacturers, and hospitals.

The main problem with the public option is that health-industry incumbents think it might work. Increasing competition and reducing drug costs may sound good to consumers, but they certainly don’t sound good to insurers and drug companies. So, even if the public option is more politically realistic than single payer, it’s still a long way from being a political reality. Which is what Senate Democrats reminded the country last week.

On Friday, 33 of blue America’s representatives in the upper chamber signed on to a resolution in support of the public option. But missing from that list were a half-dozen moderates who are facing reelection in 2018 — including the party’s vice-presidential candidate, Tim Kaine.

“We’ve had a whole lot of discussion about what’s going to happen to Obamacare but … we aren’t having discussions [about how we deliver higher-quality care at lower costs] because we keep discussing how we’re going to fund it,” North Dakota senator Heidi Heitkamp — who won election in a squeaker in 2012 — told Politico Thursday.

Among other holdouts were Montana’s John Tester and Missouri’s Claire McCaskill.

It’s hard to condemn these red-state Democrats for refusing to commit to a reform that will never pass Paul Ryan’s House — but that will expose them to Republican attacks as advocates for “Obamacare 2.0,” while providing their 2018 opponents with a load of health-industry money. True, polling suggests that, when framed correctly, the public option can garner majority support. But you can understand McCaskill finding little solace in that, when liberals have proven themselves incapable of turning out for midterms in large numbers.

Tim Kaine, however, has no excuse. He’s the party standard-bearer’s second-in-command. He has no business rebuking a policy that the sitting Democratic president sees as an essential reform to his signature health-care law.

Kaine has no right to be worrying about a Senate race in 2018. And even if he did, Virginia ain’t Montana. The Old Dominion State is growing bluer by the day; Democrats can do better there than an avuncular figure who loves the harmonica but isn’t crazy about publicly provided health care.

A Clinton campaign spokesperson told Politico that Kaine is “supportive of a workable public option for health care insurance.” But when politicians want to lend their full support to a policy, they don’t typically avoid signing resolutions that say so. Nor do they qualify their support with an adjective like workable, which projects skepticism about the program’s feasibility and establishes an off-ramp for withdrawing support from any specific public-option proposal.