Opinion writer

Most of the time, candidates in primary campaigns don’t disagree on major issues, so they have to find the points of difference and accentuate them. That’s what Hillary Clinton is doing now with Bernie Sanders on the issue of taxes, in a way that simultaneously runs to his left and to his right.

On one hand, she’s standing as the protector of the middle class. But on the other, she’s doing it in a way that accepts some conservative premises about taxes.

Here’s what the disagreement is about:

Three days after the fairly cordial second Democratic debate, Clinton’s campaign is mounting an attack against Sen. Bernie Sanders for proposals to raise taxes on the middle class that were part of the national single-payer health care bills he introduced in Congress.

“Bernie Sanders has called for a roughly 9-percent tax hike on middle-class families just to cover his health-care plan,” said Clinton spokesman Brian Fallon, referring to legislation Sanders introduced in 2013, “and simple math dictates he’ll need to tax workers even more to pay for the rest of his at least $18-20 trillion agenda. If you are truly concerned about raising incomes for middle-class families, the last thing you should do is cut their take-home pay right off the bat by raising their taxes.”

Clinton is using that 2013 legislation because Sanders has yet to release updated details of either his health care plan or how he’d pay for it. Sanders is also putting off a speech he had planned to give explaining his vision of democratic socialism, which could be because now that the primary campaign is competitive, he’s wary of alienating moderate Dems by emphasizing his leftist bona fides (but who knows; there could be other reasons).

In any case, there is a genuine division here: Sanders is willing to broadly raise taxes to pay for the programs he supports, while Clinton has adopted the same pledge she and Barack Obama did in 2008: no tax increases for anyone making under $250,000 a year.

As a campaign strategem, the appeal of that kind of pledge is clear. It reassures the bulk of voters that their tax bills won’t go up. It mitigates the effect of the inevitable Republican attacks that the Democrat is a tax-raisin’ tax-raiser who wants to raise your taxes. It’s a popular soak-the-rich message. And it doesn’t take long to explain. But it also starts from a perspective on taxes that is fundamentally conservative.

There’s a simple reason Democrats, with the exception of Obama, have tended to avoid pledges like this one: they’re the party that favors activist government, which often involves spending money, and that money has to come from somewhere. The more ambitious your program, the more taxes you’ll need to pay for it, and there may not be enough money available only from increasing taxes on the wealthy. Pledging to never raise taxes on a majority of Americans will tie your hands.

Which is exactly what happened to Obama. While he violated his promise in some small ways (there are middle class people who will pay the Affordable Care Act’s tax on tanning facilities), he’s been constrained by that pledge from supporting things he otherwise would have. For instance, while he favors paid family leave, he hasn’t supported any specific legislation to accomplish it, because the plans that are out there require broad-based taxes to fund them. Clinton’s plans for new programs were always going to be less sweeping than Sanders’ were, but she may find herself similarly constrained later.

Furthermore, on a philosophical level, a pledge never to raise taxes on the middle class runs against the liberal view of taxation. Liberals believe we ought to have a progressive system where those with higher incomes pay more, but they also believe there isn’t anything fundamentally unfair about being forced to pay taxes. Taxes pay for things we value, both collectively and individually. They pay for parks and roads and food inspectors and the military and schools and the courts and the safety net and all kinds of other things that we each benefit from directly and indirectly. In the liberals’ perfect world, everyone would feel about paying their taxes the way we do about making a tuition payment for our kids’ college or paying for that new iPhone: we’d surely rather pay less, but we’re also willing to spend the money because it gives us something we value.

That’s where Sanders’ reply to Clinton comes from: Yes, he argues, people would have to pay more taxes to fund a single-payer health plan, but it isn’t like they’d get nothing in return. They’d get health coverage. And given that every single-payer system in the world is dramatically less expensive than the American health insurance system, they’d almost certainly save money in the end, paying less in new taxes than they’d save on the insurance premiums they would no longer be paying.

But it’s hard for him to make that case if he isn’t going to be specific about exactly what his health care plan would look like and which taxes would have to be raised, and on whom, to fund it. That enables Clinton to give middle-class voters a simple message: He’ll raise your taxes, I won’t. If history is any guide, that’s likely to be pretty persuasive. But she’ll have to live with the consequences if she becomes president.