Tuesday marked the annual celebration of a politicized faux-holiday called  “National Equal Pay Day,” in which the Establishment Left rallies around a Twitter hashtag and a thousand insufferable, uninformed opinion pieces (here’s one) about the gender pay gap. Women, the progressive story goes, earn 77 cents to every man’s dollar, and Something Should Be Done.

Unsurprisingly, the right-leaning political thought machine pushed back, arguing that women’s individual choices and circumstances largely determine the subjects women study, the types of jobs women have, and the number of hours they work, which in turn determines their wages. The Wall Street Journal went as far as to point out that if similarly-qualified women could be hired for 77% of the cost of men, no profit-seeking enterprise would ever hire men again.

The left’s thinking has become more nuanced on this topic over the years. Any progressive with a brain will no longer blame pure sexism for the gap, but will instead explain how women are socialized to like children and liberal arts, and to assume more responsibility in doing housework. Which is accurate. On the population-level, men and women tend to place different priorities on different life values, and I certainly don’t know enough to argue that these tendencies are either innate or socially-sanctioned. Instead, I have one question:

What do we do?

What if it is true that social expectations push women into studying softer subject matter in college? What if most men don’t really want 3-4 months of paid paternity leave? What can “we” — as workers and employers, or through democratically-elected government — possibly do about it? Implement subject gender quotas? Impose mandatory, uniform payscales (aka wage controls)? Prohibit working beyond 40 hours? Run yet another public awareness campaign?

Megan McArdle points out that the returns to hours worked are not linear. That is, a person who spends 60 hours a week at her desk, getting more work done, will usually end up earning much more than 1.5x the salary* of the work-from-home-Fridays professional mom. We already know how to effectively close the pay gap in the professional sphere: get a degree in a STEM subject and marry a partner whose opportunity cost of domestic production is lower than yours. Beyond that, get accustomed to the reality of being a breadwinner: you’ll have a lot more responsibility, less time to pursue your passions, and no right to complain when your house-spouse spends “your” money on things that seem frivolous to you (like a mani-pedi or an Xbox).

(NB: A crazy alternative – work hard and be satisfied with having “enough,” rather than “it all.”)

There’s one important aspect to these pay gap debates that the discourse never really acknowledges: most women (and men) are never going to be business executives. There are high barriers for everybody who envisions him- or herself as an executive of the next vaguely-technology-related startup. Sure, I’d like to see more Marissa Mayerses, Virginia Romettys, Mary Barras and other women in the Fortune 500, but where the wage gap actually makes a meaningful difference in women’s lives is for low-skilled workers on the lower rungs of the income ladder.

Low-income single mothers, often without much by way of a formal education, cluster into lower-paying jobs like office administration, childcare, housekeeping, retail and other service jobs (PDF). Men cluster into construction, manufacturing, utilities, transportation, and similar industries that produce higher wages without requiring a college credential (PDF).

I don’t doubt for a second that huge barriers prevent more women from getting a job in a hardhat sector (social policy certainly alters the incentives for low-income mothers). I strongly suspect that women in such work environments would be confronted with more sexist attitudes and hostility than your average woman who sits in her office reading Slate.com and posting to Facebook multiple times per day. Lilly Ledbetter, for whom the famous wage gap Act was named, worked in a tire shop. I wouldn’t begrudge any struggling woman who walks off of a hostile work site and downgrades her paycheck by a third to be somebody’s secretary, but equal pay for equal work has to—has to—start with actually doing equal work, whether you’re operating a laptop or a forklift.

* 40 x 1.5 = 60. This is 5th-grade arithmetic, here.