In fiscal year 2004, the federal debt was 7.38 trillion dollars. The required interest to service this debt was 322 billion dollars. Trillions and billions are not meaningful quantities for peasants such as you or I, who might typically open our wallets to reveal a few singles, a couple of fives, a couple of tens, and a twenty or so. But I've done a little figurin', as they say, to bring some intuitive reality to this picture.
Envision the interest alone as a stream of bills flowing out of some Treasury building in D.C. Imagine this building ... broad granite steps leading up to an imposing main entrance, a limestone facade, lots of columns and other Romanesque architectural details. Now let's consider that stream of outgoing currency. Suppose it's only one bill wide, and the bills are exactly touching at the ends, making a seamless stream of cash. How fast does the stream travel? Well, that depends on how deep it is. The one I'm imagining is only one bill deep ... but we'll make it a twenty-dollar bill. After all, we don't want to seem cheap, and a convenience-store clerk still sometimes glares at you a little when you hand him a twenty to pay for your Diet Pepsi.
So, how long is a twenty-dollar bill?
Well, I opened my wallet just now, and -- would you believe it? -- there doesn't seem to be one there to measure. My choice is among three ones and a ten. (I get paid in a few days; I'm not always this broke.) The first thing I notice is that these bills have the same length. So I'm going to assume that a twenty-dollar bill is also that long. I measure a one-dollar bill and find that its length is 6.13 inches (to three significant figures).
Let's calculate the time rate at which twenty-dollar bills leave the Treasury. A year contains, on average, 365.26 days. So, the daily flow is $3.22E11 / 365.26 days = 8.82E8 $/day. Divide by 20 (to convert to twenties): 4.41E7 $20/day. Multiply by (1 day / 24 hr): 1.84E6 $20/hr. Multiply by (1 hr / 60 min): 3.06E4 $20/min. Multiply by (1 min / 60 s): 5.10E2 $20/s. Let's pause here to note that 510 twenty-dollar bills are flowing past, each and every second. That means they have to go pretty fast. How fast? Since each one is 6.13 inches long, the speed is 3.13E3 in/s. Converting that to the miles-per-hour familiar to every driver (I'll spare you the calculational details this time), that comes out to 178 MPH.
Now, bullets go a lot faster than that. So do jet airplanes. Race cars go faster than that ... but not much faster.
If you’d like, we can fiddle with the details. You say you'd like for the stream to take weekends off? (249 MPH.) How about the usual holidays, too? (257 MPH.) How about we only run the stream 8 hours per day, instead of 'round the clock? Now we're going fast: 770 MPH.
That high-speed stream of currency does not pay off the federal debt at all. It doesn't reduce the principal amount by one cent. It's just the interest. In fact, you can bet that it actually makes the debt bigger -- because we're borrowing to make part of the interest payments.
Well, I don't know about you, but that kind of bums me out. We've got to get those spendthrift Democrats out of power. Now, if we could just elect a good, solid, conservative, grownup, fiscally-responsible, limited-government Republican as our president ... and (I'm really dreaming now!) a Republican-majority Congress (both houses!) ... and maybe a Supreme Court with most of its members -- let's say seven of the nine -- appointed by those solid conservatives ... then I know we'd put a stop to this government hemorrhage of money. We must really have been completely crazy to have elected Gore in 2000!