That means when (or if) Chairman Tom Wheeler, the current head of the FCC, steps down, Republicans will hold a majority. And their first order of business will likely be to reverse the historic network neutrality rules that were finalized in 2015.
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The FCC is tasked with regulating wireless carriers, cable, radio and television broadcast, and internet infrastructure.
Under Chairman Wheeler's leadership, the agency passed federal network neutrality policy, which prevents internet providers like Comcast* and Verizon from charging websites like Netflix and Facebook a fee to reach internet users at faster speeds.
A record-breaking four million people commented in the FCC proceedings in favor of rules that require internet providers to treat traffic traveling over their networks equally.
Now with Rosenworcel out and Chairman Wheeler expected to leave the agency in January, the stage is set for a 2-1 Republican majority at the FCC next year. And President-elect Trump, an opponent of network neutrality, is geared to pick new leadership to reverse the rules.
Without network neutrality, internet providers will be able to create a two-way toll, charging subscribers to access the internet (which it already does) as well as charging websites for prioritized access to reach their users.
That means that smaller, new online businesses that can't afford to pay to reach users at faster speeds will be relegated to the slow lane, making it difficult to compete with already established sites — especially if websites that are already extremely profitable, like Facebook, get to set the price.
The FCC is led by five commissioners, with three seats typically representing the party of the president in office. Without Rosenworcel, the FCC will be staffed by four commissioners split on party lines, but that should change in January, when President-elect Trump takes office and is supposed to appoint a new chairman of the agency.
Once a new president is elected, the chairman usually leaves, but he doesn't necessarily have to. Chairman Wheeler could stay on the commission and carry out the rest of his term as a commissioner under the leadership of a new chairman. Wheeler's term does not expire until 2018, which would leave the commission split even on party lines until President-elect Trump nominates a new commissioner to replace Rosenworcel.
And the FCC can carry on with business, even without immediately filling Rosenworcel's open chair with a Republican. The previous FCC Chairman, Julius Genachowski, left the agency in March 2013, for example, and wasn't replaced until eight months later in November when Wheeler was confirmed.
Trump hasn't named his pick for FCC chief yet, but the two advisers the president-elect appointed for his transition team, Jeff Eisenach and Mark Jamison, are both fierce opponents of network neutrality and are expected to guide the agency in a direction that will be more favorable to internet providers than to Silicon Valley companies.
Even if Trump's FCC does immediately start to sketch plans for reversing network neutrality, the current rules won't evaporate overnight. The commission will have to open a new rulemaking process to undo the previous order, and that may take well over a year, if not longer.
—By April Glaser, Recode.net.
Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com. CNBC's parent NBCUniversal is an investor in Recode's parent Vox, and the companies have a content-sharing arrangement.