Well, that certainly is the MAIN reason we have a federal government. But there are a few other powers enumerated in the Constitution: a common currency, the post office (ironically enough), regulate interstate commerce--which has been badly abused but which can serve a legitimate purpose (e.g., I don't mind that the FDA makes sure preescription drugs sold nationally are safe).
But the point here of course is that there should be no "Government Motors." Romney is right on this.
Mr. Henrickson -- I thank you for the response and at the risk of thread drift, that part of Article I (Section 8, Clause 7) has been a thorny issue for about the last 20 years when private enterprise (notably FedEx) and electronic communications have made a government-run postal system an anachronism.
The so-called "Postal Clause" is subject to interpretation and, I think, its original intent was lost over the years giving us the travesty now known as the USPS. I personally favor a very strict construction of what Clause 7 means which would allow the government to remove itself entirely from anything involving the delivery of mail. The USPS is a money-losing proposition and is in the firm hands of union thugs. In an ideal world, I'd like to see it eliminated entirely. But would that view that I favor be fully in harmony with the Constitution (without taking the leftist view of a "living, breathing" document)?