Do you see a problem with the dwindling elephant population too?
Yes, of course.
If so, are you able to judge which is the greater problem?
You are engaging in a classic false dilemma fallacy.
Do tell, how the prohibition on selling 50-year-old ivory helps the dwindling elephant population?
Lots of existing ivory becomes illegal, leading to a local drop in value, leading to lots of US ivory being traded to countries where it isn't illegal. Right?
So that first of all that sets up excellent opportunities for police sting operations. But it also drives down prices (at least for a few years), making elephant poaching less lucrative.
In parallel to that, the US is setting an example. A lot of countries copy US criminal laws rather than thinking them up from scratch (the War on Drugs being the textbook example), and since almost everyone loves elephants and the ivory trade is a huge and growing threat to them, there'll be a particularly low threshold to copying this one.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.