With its final open meeting of the year coming up Thursday, the nation's top telecom regulator could be deadlocked in a 2-to-2 partisan stalemate by week's end due to the U.S. Senate's failure to appoint Jessica Rosenworcel, a Democrat, to the Federal Communications Commission.

Rosenworcel serves as one of three liberals on the five-member panel, but must leave the FCC on Dec. 31. The Senate adjourned last Friday without confirming Rosenworcel, prompting reports that the nomination had failed.

If Rosenworcel departs as expected, it would leave the FCC with two Democrats and two Republicans — a tie that could mean no new action from the agency until President-elect Donald Trump nominates his own pick to fill Rosenworcel's open seat. In the meantime, Republicans could even gain a 2-1 majority if the FCC's Democratic chairman, Tom Wheeler, resigns — giving the GOP the power to roll back many of Wheeler's policies, such as net neutrality and privacy rules for Internet providers.

Wheeler said last week that he was willing to step down “immediately” if it would ensure that Rosenworcel would be confirmed. But that commitment, made to Senate Minority Leader Harry M. Reid, may have been too little, too late.

Reid and his Republican counterpart, Majority Leader Mitch McConnell, were said to be working on a deal to confirm Rosenworcel late last week. But in the closing hours on Friday, Senate aides said there did not appear to be enough time.

The confirmation battle exposed a long-simmering rift within Democratic ranks. Earlier, Rosenworcel had disagreed with Wheeler over an FCC proposal that would have allowed non-cable companies such as Google and Amazon to build their own set-top boxes to compete with those that consumers rent from their existing providers. A vote on the proposal, scheduled for September, had to be tabled because it lacked the support it needed to pass.

Rosenworcel's lapsed nomination could be brought back in 2017. But policy analysts believe it is a long shot because Trump has the option to nominate someone else.

Meanwhile, the Senate's failure to come to a deal on Rosenworcel puts the spotlight on Wheeler, whose term as a commissioner does not expire until 2018. If he follows custom, Wheeler would step down to make way for Trump's nominee for chairman, and he would have the option to stay on as a regular commissioner for the duration of his term.

But Wheeler has not committed publicly to relinquishing his position, raising questions about his strategy during the final weeks of the Obama administration.

We talk to FCC chairman Tom Wheeler re: cable companies and set-top boxes (Jhaan Elker/The Washington Post)

If he does leave the FCC entirely along with Rosenworcel, it could create a 2 to 1 imbalance on the panel with Mignon Clyburn serving as the agency's only Democrat. That could allow Republicans to ram through policy changes aimed at undoing much of Wheeler's work for the past three years.

Some analysts say that Democrats could temporarily stymie the Republican-controlled FCC if Clyburn also resigns, leaving the agency without a quorum. With no Democrats present, the FCC would not be able to conduct business, according to Berin Szoka, president of the right-leaning think tank TechFreedom.

But that victory could be short-lived, he added: While the law states that no more than three members of an independent agency can be of the president's party, that wouldn't keep Trump from stocking the FCC with his most loyal allies.

At that point, it would be up to Senate lawmakers once again to decide how to move forward.