Sorry to disappoint folks across the spectrum who are trying to turn Biden into a sharia creep or a beacon of cultural understanding but the truth is:

Biden absolutely did not use "Inshallah" the right way.

When Trump was talking about making his tax returns public Biden quipped: "When? Inshallah?"

Set aside for the moment that he pronounced Inshallah more like Enchilada, this is the wrong usage.

Inshallah means "if God is willing" which yes, people do sometimes use to disguise their intentions to never do something.

But that is precisely the problem, when it is used this way, it is used by the person DOING the deceiving, not the one calling it out.

Biden referred to Inshallah as a time.

When? he asked, Inshallah?

That's not the proper usage. He was looking to signal to a time that doesn't exist to call out Trump's deception. In English one might say "When? When pigs fly!"

But lucky for @JoeBiden we actually have an equivalent idiom in colloquial Arabic. It's Bokra Fil Mish Mish. Which means, Tomorrow in Apricot Season. (don't ask)

So if he said "When? Bokra fil Mish Mish?"

He would've had the proper Arabic usage and I would have been impressed.