Former Treasury Secretary Lawrence H. Summers recently suggested stopping the production of $100 bills, ostensibly to deprive criminals oftheir favorite form of cash.

Mr. Summers may or may not get his way. But here's a potential trade-off: If the hundred-dollar bill is destined to vanish from cash registers, how about bringing back one of the jauntiest denominations of American spending money, one that many citizens, through no fault of their own, have never felt in their pockets: the 50-cent piece?

This year, the U.S. Mint will manufacture for public circulation-if recent numbers are a guide-around nine billion pennies. The mint will produce around two-and-a-half billion quarters, almost three billion dimes and a billion-and-a-half nickels.

The number of 50-cent pieces that the mint will manufacture and release for general circulation in 2016 is the same it has been for the past 13 years: zero.

No one saw the half-dollar's demise coming. The disappearance from everyday usage of what once was a taken-for-granted, constantly present American coin is a tale of unintended consequences, and of how history can blindside and do away with even the most standard and noncontroversial aspects of the nation's life.

The 50-cent piece was always a highly useful, immensely popular coin. The thing had heft and a bit of swagger: It was bigger and heavier than the smaller-denomination coins, but not so unwieldy that it was uncomfortable to carry. There was a touch of ring-a- ding-ding to having it in your pocket. You had to resist the impulse to pull it out and flip it.

And-most important-you could make significant daily purchases with it, and walk away with change. The mint had been putting half-buck pieces into circulation for as long as the U.S. had been manufacturing coins; by the early 1960s, a 50-cent piece would buy you a quart of milk, or an issue each of Sports Illustrated and Life magazines, or enough Snickers bars and packs of Beech-Nut Spearmint gum to get you and a couple of buddies through the afternoon, or a gallon-and-a-half of gas, or a bleacher seat at a big-league baseball game. It was real money. Its future seemed secure.

Then, in November 1963, President John F. Kennedy made his trip to Dallas.

As the nation grieved in the weeks after the assassination, government leaders scrambled to come up with ways to honor Kennedy's memory. President Johnson and Congress thought it would be a fine idea to speedily replace Benjamin Franklin's face on the 50-cent piece with Kennedy in profile. A touching gesture. What could go wrong?

By February 1964 the Kennedy half-dollars were being pressed, with public release scheduled for March. As soon as banks began offering the coins, long lines formed. People wanted them, all right-not to spend, but to keep. Banks had to ration, limiting the number that individuals could request. A mystique instantly grew. If you had one of those coins, you knew to hold on to it.

Coincidentally and concurrently, the price of silver was rising to the point at which the worth of the material within the 50-cent piece might soon surpass the face value of the coin. Precious-metal traders were hoarding half-bucks, both the new Kennedys and the old Franklins, in anticipation of melting them down and profiting.

The coins seemed to all but evaporate from the public scene. The U.S. Mint, by 1971, had eliminated silver from the composition of the half-dollars, but by then people had become accustomed to their absence. As the years went by, stores stopped making space in cash- register drawers for them; vending machines wouldn't accept them; banks had to request them from the Federal Reserve for the few customers who desired them; and younger Americans were unaware the coins even existed.

The mint stopped putting half-dollars into circulation in 2002. It still manufactures commemorative and special-edition 50-cent pieces for collectors, sold to the public at a premium, but when the mint offers a mounted set of four Kennedy half-dollars for $99.95, you'd feel like a fiscal idiot spending the coins at the corner 7-Eleven.

The man described by mint officials as the nation's leading authority on the history of coins, Q. David Bowers, said that, in terms of daily commerce, the half-dollar isn't coming back. "It's a dead issue," he told me. Had the government never removed Ben Franklin's portrait, the 50-cent piece would likely still be thriving today, as utilitarian and ubiquitous as the George Washington quarter. But-no one planned it this way-it turns out that a coin can be so popular that it goes out of business.

To read the complete article (subscription required), see:
The Half-Dollar's Accidental Demise (http://www.wsj.com/articles/the-half-dollars-accidental-demise- 1456695824?cb=logged0.6362204554050646)