Exercise 3: What Changed After South Dakota v. Wayfair, Inc. — Possible Solution
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WHAT CHANGED
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Per this chapter, the 2018 Supreme Court decision in South Dakota v.
Wayfair, Inc. overturned the prior physical-presence-only standard
that had been established by Quill Corp. v. North Dakota (1992). Before
Wayfair, a state could only require a business to collect its sales
tax if that business had some physical presence there (an office,
warehouse, or employee). After Wayfair, a state can also require tax
collection based purely on economic activity - once a remote seller
crosses a defined threshold of sales or transactions in that state.

WHY NO PHYSICAL PRESENCE CAN STILL MEAN A TAX OBLIGATION
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Per this chapter, this is exactly what "economic nexus" means: nexus
(the legal trigger for a tax obligation) can now be established
without any physical footprint at all, purely by selling enough into
a state. A store with no office, warehouse, or employee anywhere near
a given state can still cross that state's own sales/transaction
threshold and become legally obligated to collect that state's sales
tax as a result.

WHY THIS WORKS AS AN ANSWER
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It correctly identifies the prior standard the case overturned
(physical presence, per Quill), correctly identifies what replaced it
(a purely economic threshold), and correctly explains why that shift
is precisely what allows a remote seller with zero physical presence
to still owe tax in a given state.