Math doesn't add up on state Social Security tax cut

Now that the first of this year's intergenerational feast days is behind us — and before the next one arrives — let's ponder an intergenerational tussle that seems headed to the 2019 Legislature, and maybe also to a dinner table near you.

The issue: Should the state income tax continue to be collected on the Social Security income of middle- and upper-income elders? (Low-income recipients' benefits are already spared.) Or should Minnesota join the 28 states with an income tax (plus nine that have none) that keep Social Security income out of the state tax collector's reach?

Exempting Social Security income from state taxation is an idea with a big following, and not just among the silver-haired set. Republican legislators have been pushing for a full exemption ever since the state budget's bottom line moved from persistently negative to positive territory.

When state candidates came to call on the Star Tribune Editorial Board this year, pretty much all of the Republicans — and more than a couple of DFLers — mentioned their support for a Social Security exemption. When I asked why they like the idea, they often made several arguments that don't quite jibe with the facts:

• "Taxing Social Security benefits is double taxation, since those benefits are derived from income on which taxes were already paid." Congress anticipated that argument several decades ago and addressed it by exempting 15 percent of Social Security benefits from federal income taxes. The state income tax offers the same 15 percent exemption.

• "Seniors struggle financially. They need every penny Social Security provides." State tax policy already recognizes as much. Married couples with income other than from Social Security of less than $32,000 (for singles, it's $25,000) already owe no state or federal income tax on their benefits. Married couples with non-Social-Security incomes of up to roughly $100,000 (for singles, it's roughly $78,000; both amounts are adjusted annually for inflation) pay tax on a reduced portion of those benefits — and that tax-free portion was enlarged by the 2017 Legislature.

• "Seniors are moving away because Minnesota taxes their Social Security income." Plenty of anecdotes back that up, but economic research does not. "Elderly interstate migration is fairly rare and unresponsive" to Social Security tax policy changes, concludes an oft-cited 2014 study by economists Karen Smith Conway and Jonathan Rork.

• "Seniors have worked hard their whole lives. They deserve a break." Utter those lines at your next multigenerational dinner, then brace yourself for the millennial rebuttal. The kids I know will come back with the claim that they have it harder than their parents did in the 1970s and 1980s. Comparing four key household cost drivers — the three H's, housing, higher education and health care, plus two C's, child care — they're right:

The median price of a house sold in the U.S. in January 1975 was $37,200, or about $175,000 in today's dollars. According to the St. Louis Federal Reserve Bank, today's median American house price is nearly twice as high, $325,200.

Tuition and fees at a public four-year college or university in America cost an average of $430 per year in 1971-72, or $2,660 in today's dollars. According to the College Board, average public four-year tuition and fees in 2018-19 came to $10,320. That difference helps explain why 70 percent of today's college graduates owe student loan debt.

American household expenditures on health care as a share of personal income grew from 4 percent in 1960 to 6 percent in 2013, according to a 2015 report issued by the Centers for Medicare and Medicaid Services.

American families with employed mothers spent on average $42 per week on child care in 1985, the Census Bureau reported in 2011. That's $98 in today's dollars — less than half of today's U.S. average cost of center-based child care, $211 per week.

Those stats are enough to make this baby boomer blush. They ought to bother state lawmakers, too. It's sometimes said that the overriding purpose of state government is to set the table for the next generation's prosperity. The soaring of these household costs suggests that state government hasn't been setting a very bountiful table.

If Minnesota exempts all Social Security income from state taxes, state government's ability to invest in future human capital will be depleted, a little now, a lot more later. Baby boomers are exiting the workforce in big numbers now, but they're not all at their leisure yet. The number of Social Security recipients in the state will keep growing rapidly in the next decade. That's why exempting Social Security from state taxation now would take an ever-bigger bite from the state treasury — $353 million this year, $387 million next year, an estimated $640 million by 2027.

Keep that money in senior hands rather than state coffers, and it might be spent in economically useful ways. But I ask my fellow grandparents: Would that money do more good if it allowed more disadvantaged kids the benefits of early childhood education? Or if it helped relieve today's parents of their college loan debt, so that they could save for the grandkids' higher ed? Or if it helped hold down the out-of-pocket costs of health care for those not yet eligible for Medicare?

I suspect that the real reason so many politicians favor a Social Security exemption from state income taxes is that they know that elders are more faithful voters than young adults are. The pols expect that giving seniors a tax break would bring them a reward at the polls.

But that must mean that they think Minnesota's seniors are a selfish lot, concerned more for our own financial comfort than for the well-being of coming generations. We boomers weren't perfect parents. But I'd like to think that we're better grandparents than that.

Lori Sturdevant is a Star Tribune editorial writer and columnist. She is at lsturdevant@startribune.com.