US residency tests

In speaking to David Taxable John Cullinane may have misheard just a few words (which is of course frequently a taxing problem listening to cartoon voices) and the American 'green card test' has become muddled with the 'substantial presence test' in the article on residence (Home is a range).

David Taxable clearly has sensible friends such as Lucy given that she spends each winter in the Rockies. From a US tax perspective she becomes a US resident either if she meets what is known as the 'substantial presence test' or if she has a 'green card'. If she has a green card she is always a resident of the United States until she formally abandons the green card.

The substantial presence test is a simpler mechanical test of day counting where almost any day of presence is counted (none of this nonsense about deciding...