This educational guide is based on the linked primary sources. It is not a Court publication, is not affiliated with the Court, and is not legal advice.
In brief
Overview
According to Marty J. Jackley, on behalf of South Dakota (Petitioner), according to Marty J. Jackley, on behalf of South Dakota (Petitioner), south Dakota argues that the Quill decision causes the state to lose massive sales‑tax revenue needed for education, healthcare, and infrastructure.
According to Marty J. Jackley, on behalf of South Dakota (Petitioner), according to Marty J. Jackley, on behalf of South Dakota (Petitioner), south Dakota also says that small businesses on Main Street are harmed because out‑of‑state remote sellers have a price advantage under Quill.
According to Mr. Isaacson, Wayfair contends that the software required to calculate taxes for thousands of jurisdictions is error‑prone and complex for retailers.
According to Mr. Isaacson, Wayfair further argues that the real competition is between large omni‑channel retailers, and that higher entry costs will deter small and medium‑sized companies, increasing market concentration.
Background and question before the Court
What each side argues
South Dakota (Petitioner)
According to Marty J. Jackley, on behalf of South Dakota (Petitioner), according to Marty J. Jackley, on behalf of South Dakota (Petitioner), south Dakota claims that the Quill decision deprives the state of essential sales‑tax revenue.
According to Marty J. Jackley, on behalf of South Dakota (Petitioner), according to Marty J. Jackley, on behalf of South Dakota (Petitioner), south Dakota asserts that small in‑state businesses are harmed because out‑of‑state sellers have a price advantage.
According to Marty J. Jackley, on behalf of South Dakota (Petitioner), according to Marty J. Jackley, on behalf of South Dakota (Petitioner), south Dakota urges the Court to apply the doctrines from Complete Auto regarding tax assessment, discrimination, apportionment, and substantial nexus.
Wayfair, Inc. (Respondent)
According to Mr. Isaacson, Wayfair argues that the software used to calculate taxes across thousands of jurisdictions is riddled with errors and is not a simple “silver bullet.”
According to Mr. Isaacson, Wayfair notes that the competition is actually between large omni‑channel retailers, and that higher barriers to entry would deter small and medium‑sized firms, increasing concentration.
According to Mr. Isaacson, Wayfair raises the issue of stare decisis, arguing that even if the Court’s prior rulings were mistaken, there is value in maintaining settled expectations.
What happened at oral argument
Justice Ginsburg asked Mr. Stewart a follow‑up question during oral argument.
According to Justice Breyer, justice Breyer inquired about the cost to Amazon of voluntarily complying with tax collection.
What the Court decided
Why it matters
Terms to know
No glossary terms are available for this guide.
Primary sources
Read the source materials on the official site or open the immutable repository copy used for this guide.
- de95e1786a5b0267d020-r1-8682f51d917a414d.pdforal argument transcript
Guide generated September 26, 2026. Automated validation accepted this version.