For some reason, I have it in my head that a non-resident alien cannot open an IRA (specifically a roth IRA, but a resident alien with an ITIN can open an IRA. Can anyone point me to the rules about this or did I just make up those rules? Thanks so much!

A non resident may open an IRA as long as they have an TIN (ss or ITIN) and earned income from the year they are contributing for.

Resident alien yes and again with a TIN and earned income for year contributing for.

For the non resident if they don't have a W-8 there is mandatory 30% WHH if they do have a w-8 on file they may have the same WHH options as a us person.

Thank you so much, I could not find that information in any IRS publications. I may have overlooked it though. Do you know if it is in Pub. 590?