Yes. Constitutional amendments require two kinds of super-majorities just for this reason. Even if technically an individual mandate didn't require a constitutional amendment (I believe it did), the spirit of the amendment process indicates that you should get 2/3 support to propose and 3/4 support to ratify fundamental changes to our government.
The Supreme Court, with a 5-4 majority of conservatives, ruled otherwise. So apparently, it didn't require a Constitutional amendment. At all. A law was plenty.
