The Constituton isn't magic. No matter what it says, courts applying it have always been able to rule anything constitutional (or, conversely, unconstitutional.) Like any set of rules for human behavior, it is not self enforcing.

The Constitution has never, from day one, been a protection against the power of the federal government, it is at most a warning about what the public intends to limit the federal government to, and it has force exactly to the extent that the public is willing to follow up on that warning.