The intensely competitive nature of the Internet is vital to the American economy and democracy. So we worry that rules proposed this month by Julius Genachowski, the chairman of the Federal Communications Commission, to guarantee the Internet’s openness may not be able to guarantee the survival of that competition.

Any new rules must prevent broadband service providers from foreclosing on competition. As proposed, the rules appear to come up short.

We supported an earlier attempt by the F.C.C. to classify access to broadband as a telecommunications service because it is the modern version of phone lines that carry our voices. This would have given the commission much more power to regulate broadband access than the current definition as an information service.

But an assault against this strategy led by the telephone and cable giants convinced the F.C.C. chairman to drop the reclassification and propose a more modest set of rules. It is important that the modest regulations be strengthened before the full commission votes on them on Tuesday.