When Donald Trump unveiled his child-care proposal this week, he made a claim that seemed absurd on its face.

He said Hillary Clinton “has no child-care plan.”

He repeated the charge on his website, carping that Clinton “claims she wants to cap a family’s child care expense at 10 percent of income, but provides no details.”

Journalists and Clinton sympathizers called the statement crazy, noting that Clinton released a bold, detailed policy ages ago. The Clinton campaign likewise tweeted a snarky retort to the accusation that she had “no plan,” saying: “It’s literally right here,” with a link to her website.

But if you click that link, you’ll discover that Trump is ... not wrong.

Hey, every once in a while even a blind squirrel finds a nut.

Befuddlingly, Clinton hasn’t ever explained how she’d achieve her breathlessly praised promise to cap child-care expenses at 10 percent of family income. She’s merely declared she would, somehow. Precise plan TBD.

It’s like promising to cure cancer by curing cancer, or to reduce the deficit by reducing the deficit, or to — ahem — destroy the Islamic State by destroying the Islamic State. (Maybe she has a secret plan she doesn’t want the enemy to know.)

This should have been a slam-dunk for Clinton. She has fought on behalf of children her entire career, as she frequently reminds voters. Helping working mothers is one of her signature issues. And she’s supposed to be the policy wonk in the race, the one who “sweat[s] the specifics because they matter,” whose math adds up.

Clinton first made this very-precise-sounding “10 percent” pledge in May. At the time, she said only that the 10 percent cap would be realized by “significantly increasing the federal government’s investment in child care subsidies and providing tax relief for the cost of child care to working families.”

Details about what the mix of subsidies and tax cuts would look like would come “later,” her campaign said.

For months, whenever I asked for those details, I was again told “later.” Wednesday, in my most recent conversation with campaign aides, I was informed that the 10 percent was not an explicit “hard cap” but rather a general “goal” that could be achieved through other policies Clinton has laid out.

These include paid family leave, universal pre-K, and scholarships for student-parents (who, while a worthy population, hardly constitute all parents struggling with child care).

Of course, Clinton proposed those ideas back in May. If they were sufficient to reach that 10 percent “goal,” why did the campaign say then that details of the 10 percent plan would arrive “later,” I asked?

The campaign then referred me to some of Clinton’s more recent, still-vague comments about expanding the child-care tax credit and state block grants for child care. But again, it provided no details or numbers that would enable anyone to check whether the 10 percent goal was successfully achieved; how much the plan would cost; how it would be paid for; or whether it would be a big giveaway to rich people (often a risk with subsidies administered through the tax code, which Clinton’s plan may or may not be).

Maybe it sounds persnickety to ask for details. But even the chronically policy-averse Trump has managed to release details of his child-care proposals, which rely exclusively on tax breaks.

In fact, those details are how we know Trump’s plan is bad.

We can tell from what he’s released, for example, that his policy will primarily help the rich, despite his claims to the contrary. And we can tell that his way of paying for the tax breaks — additional economic growth — is fantasy.

Goals are easy. Figuring out how to achieve them is hard. But that’s supposed to be the part Clinton really digs. Or, rather, “sweats.”

For all the complaints that Trump is “graded on a curve” and Clinton held to a higher standard, it’s unclear why she’s been able to get away with never substantiating her widely publicized promise, and why it’s enjoyed so much eager praise. Maybe we’ve let her skate because on so many other issues she has released detailed, thoughtful white papers. Maybe everyone reflexively assumes that on child care, a signature campaign issue, there must be a densely footnoted white paper hiding out somewhere, too.

Here, she’s been given benefit of the doubt that wouldn’t be afforded Trump, because he’s previously expressed disdain for policy specifics. Strange to see the candidates reading from each other’s scripts.

© 2016, Washington Post Writers Group

Email: crampell@washpost.com. Twitter: @crampell.