The reason they ignore the 10th Amendment is based on a decision during the FDR era where the SC had a ruling about a farmer.
They said if the farmer COULD engage in interstate commerce, even if he didn't actually do it, then it comes under interstate commerce clause. That means the 10th Amendment is completely ignored.
The person who wrote that decision was Robert Jackson.
When John Roberts was interviewed as a SC candidate, he said his favorite justice was Robert Jackson.
Roberts would then write the Obamacare decision in the same light: if the government wants you to buy something, you have to pay a tax if you don't.
Ginsberg and Roberts both have to be replaced.