Ah, you are thinking logically. This is a mistake when it's got anything to do with the orange rapist.

What happened is something along the lines of this...
"Sir. The poors are complaining about beef prices again"
{Obese orange imbecile flies in to a narcissistic rage, then shits himself}
"Sir. Why don't we import beef from Argentina?"
{Shits himself again} "Press conference, now."
...
"I've called you all here today because I myself have had a tremendous, bigly, perfect idea" {performs that stupid fucking grin of his, puts his thumb up, shits himself} "My, and my alone, idea is to import beef from Australgentina to bring prices down. You know my uncle was a cow, the best cow, yuge big udders he had. Everyone said it. Anyways, if prices go down this was all my idea" {Puts thumb up. Stupid grin. Shits his pants again}

There you go. Basically if he hears something that seems like a good idea, or if he thinks there's a good soundbite from it, then it's now his idea.
If it fails then it was a federal thing to blame. Or Obama. Or Biden. Or both.

Tarrifs really. His favourite toy. When he 'decides to import Argentinian beef', i presume this means he means he will remove or reduce tarrifs on beef from Argentina, and potentially lower or streamline any bureacracratic hurdles - you know silly things like quality and disease control - stuff like that which Republicans hate. That'll thereby make Argentinian beef much cheaper for US wholsalers.

As usual, this is a disaster of his own making, as he imposed an additional 50% tarrif on Brazilian beef - which was a large source of US supermarket beef, on top of their pre-existing 23.6% tarrif.. Taking it to nearly 75% tarrif, and this was during an (ongoing) parasite outbreak in Mexico that was already lowering beef availability to the US and causing price rises. So, shock.. supermarket beef prices shot up rapidly in response and have stayed there.