Franken said he fears that means corporations will reserve online "fast lanes" for themselves.
"Imagine if a cable news network could get its website to load faster on your computer than your favorite local political blog. Imagine if big corporations with their own agenda could decide who wins or loses online. The Internet as we know it would cease to exist," Franken wrote. "That's why net neutrality is the most important free speech issue of our time."
While campaigning at Google before the election, President Obama vowed, "I will take a backseat to no one in my commitment to network neutrality.
"Because once providers start to privilege some applications over others then the smaller voices get squeezed out and we all lose," Obama said. "The Internet is perhaps the most open network in history. And we have to keep it that way."
Today Franken wrote, "Grassroots supporters of net neutrality are beginning to wonder if we've been had."