The Internet is a vital platform for innovation, economic growth and
free expression in America. And yet, despite two prior FCC attempts,
there are no rules on the books to prevent broadband providers from
limiting Internet openness by blocking content or discriminating
against consumers and entrepreneurs online.
—Protecting and Promoting the Open Internet May 15, 2014 fcc.gov
There's a possibility that Internet Service Providers discriminate against bitcoin traffic either by making it more difficult, setting limits, charging a toll, or by blocking it altogether. This could prevent nodes from relaying transactions and relaying blocks, either of which would undermine the network.
The prodigiously talented members of the community would no doubt come up with workarounds, perhaps ways of obfuscating bitcoin related traffic. This could possibly result in an arms race. It could ultimately drive the bitcoin community to build its own network which some have already proposed.