Democratic lawmakers will unveil a piece of bicameral legislation Tuesday that would force the Federal Communications Commission to ban fast lanes on the Internet. The proposal, put forward by Senate Judiciary Committee chair Patrick Leahy (D-Vt.) and Rep. Doris Matsui (D-Calif.), requires the FCC to use whatever authority it sees fit to make sure that Internet providers don’t speed up certain types of content (like Netflix videos) at the expense of others (like e-mail). It wouldn’t give the commission new powers, but the bill — known as the Online Competition and Consumer Choice Act — would give the FCC crucial political cover to prohibit what consumer advocates say would harm startup companies and Internet services by requiring them to pay extra fees to ISPs.