There's probably some people that know without me telling them that this is the number for Franklin half dollars lol. Had some money left over from my Amazon gift cards, and just got a few Franklin half dollars to get me started, so I thought why not. This seems like one of the US coins that never really got much of a chance, only running 15 years. Apparently it only got popular to collect after the fact (from what I hear; I wasn't around yet to know this first-hand). For me it falls right in the middle between "classic" and "modern" and I've always liked the look of it. Shouldn't be too difficult or expensive to try to finish this series.
It was cut short by the Kennedy assassination. Otherwise it still would have been phased into clad and we'd probably be getting Franklin half dollar mint products to this day.
There's actually a law that says a coin design has to run for 25 years before it's changed, though exceptions have been made to it several times. (The tiny eagle on the reverse of the Franklin half dollar is due to another law saying any coin with a higher denomination than a dime has to have an eagle on the reverse.) It was suggested that Kennedy be put on the dime, but Jackie Kennedy didn't like the idea of FDR being taken off of that, saying that JFK admired him. Interestingly enough if they wanted to stick the the 25 year rule, Jefferson nickels would have been eligible. I think another reason they settled on half dollars was that at the time, it was the only circulating denomination to not have a president on it. In an alternate timeline where JFK was not assassinated, Franklin half dollars probably would have continued and we'd have clad Franklin halves by now.
Actually, that's not - quite - the law. 31 U.S. Code § 5112 - Denominations, specifications, and design of coins https://www.law.cornell.edu/uscode/text/31/5112 And of course most coin legislation says "not withstanding ..." and then goes on to direct things that are otherwise against the law. But, according to 31 USC § 5112(d)(2), the secretary COULD change the Jefferson Nickel design (introduced in 2006) tomorrow. But they would then not be able to order another change until 2031. Or could they? A 2025 change would seem to reset the clock to 2050. But again there is that pesky ONCE clause. A 2026 change would reset the clock to 2051. etc. Food for thought.
Well everything has exceptions. Congress can pass legislation that changes a coin design whenever they want. But if the design's been running at least 25 years, the Secretary of the Treasury can change it without waiting for Congress's say-so basically. I think your interpretation is correct, but that's not how they've treated it... they've treated it as if it means every 25 years, not once within 25 years. (But regardless they've made multiple exceptions anyway; the Washington quarter was introduced when the Standing Liberty design was only 16 years old.) The current obverse of the Jefferson nickel only dates back to 2006, but the reverse is essentially the same as it's been since 1938 (except for 2004-2005). Other random thoughts: The tiny eagle on the reverse is somewhat ironic, considering that Benjamin Franklin was not fond of the eagle, and suggested the turkey should have been our national symbol instead. In an alternate universe where the Franklin halves continued to the bicentennial, Independence Hall would seem even more appropriate on the reverse. Also Washington and Franklin would have had far more connection to the events being commemorated, leaving Eisenhower as the odd one out lol. Still surprised they didn't do anything with the Jefferson nickel for the bicentennial.
