Quadrillion-dollar national debt? Chew, don’t nibble, on this math.

When agitated, which he often is, Rep. Chip Roy, 50, large and fit, with a bald head and a goatee, resembles an Easter Island statue with an attitude. Arithmetic explains this Texas Republican’s seriousness about the need to restrain federal spending by restructuring entitlement programs. Someday. His realism, a product of experience on Capitol Hill and in presidential campaigns, tells him this task is not for today.

Meanwhile, he envisions saving $3 trillion over 10 years by cutting the “woke, weaponized and wasteful” bureaucracy to fiscal 2019 levels, while maintaining defense spending at current levels. But pruning annual spending by $300 billion from unspecified and presumptively unpopular (“wasteful”) programs will not banish this arithmetic:

The American Main Street Initiative, a think tank, says the Obama, Trump and Biden administrations compiled more debt held by the public, adjusted for inflation, than did all previous presidents combined. And if the national debt rises for 60 years at the rate it has risen during the previous 30, it will then exceed $1.5 quadrillion. (A quadrillion is a thousand trillions).

Roy would address these numbers with strong work requirements for Medicaid, SNAP (the Supplemental Nutrition Assistance Program) and some other programs and by shrinking (by unspecified measures) healthcare and prescription-drug costs, “among other things.” Politics is the art of prudently defining the possible.

Which does not include the House Republicans’ announced goal of balancing the budget in no more than 10 years — and without touching Social Security or Medicare (with other entitlements, almost two-thirds of the budget). Or debt service (more than 8%), which is not optional. The Manhattan Institute’s Brian Riedl notes that inflationadjusted defense spending, currently 13% of the budget, has been shrinking since 2008, when the world was less dangerous than it now is.

Any proposed reform legislation with the adjective “comprehensive” attached to it is probably a feel-good futility. However, nibbling at a problem — say, increasing the age for Social Security eligibility — can produce huge long-term savings. Again, the Main Street Initiative:

“The percentage of the U.S. population that is over age 75 is roughly the same as the percentage that was over age 65 when Social Security first began, yet the eligibility age for receiving full retirement benefits has been raised just two years (from 65 to 67) over the past eight decades.”

Roy emphatically does not favor raising the Social Security eligibility age. Making entitlement facts congruent with biological facts is currently politically unthinkable even though — no, because — it would save many trillions over 75 years. Sally Pipes of the Pacific Research Institute notes that 17% of the population is over 65, up from 10% when Medicare was passed in 1965. Pipes says that raising the Medicare eligibility age from 65 to 67 (life expectancy at 65 is 17 years for men, 19.8 years for women) would save up to $22 billion annually. And the savings would compound through reduced debt service.

The only adequate savings — savings commensurate with the structural debt crisis — require structural reforms of entitlement programs. Politically risky things cannot, however, be done in election years or years immediately preceding election years, which are the only years there are.

Structural changes to entitlements, Roy believes, will require a Republican president willing to sign reforms that congressional Republicans would send to him or her after economizing “elsewhere right now.” And “unleashing” energy production. Etc.

Tomorrow is, of course, always a day away. Meanwhile, channeling his inner Andrew Jackson, Roy favors this nibble from federal spending: Congress should confine itself to funding truly national rather than merely state projects. In 1830, Jackson vetoed the Maysville Road bill that would have funded a 60-mile road in Kentucky between Maysville and Lexington. However, he favored extending the 620-mile National Road connecting Maryland and Illinois. Today’s Washington thinks everything is connected to everything, so everything is Washington’s business.

Budgeting supposedly is Congress’s primary business, which Roy and kindred spirits in the House Freedom Caucus should encourage Congress to resume doing. Not since 1996, when Roy was a stripling of 24, have all 12 required appropriations bills been separately signed into law. Instead, there are indignities like the 4,155-page take-it-orleave-it omnibus bill presented to (supposed) legislators in December.

Before Roy leaves Congress — borne away on his shield, having given the last full measure of devotion in pursuit of substantial spending restraint — he might see such “regular order” become regular again. And “quadrillion” not become a regular component of the vocabulary describing the nation’s fiscal trajectory.