The loss of Senate seats in Ohio and West Virginia tipped the balance of power in the upper house of the US Congress.

The Republican Party has reclaimed control of the United States Senate, ending two years of leadership from the Democrats.

Tuesday’s general election saw a third of the upper chamber in Congress — or 34 seats — hit the ballot, of which approximately nine were competitive.

The Democrats were vulnerable to losing their grip on the chamber, given their narrow majority. A coalition of four independent senators and 47 Democrats gave the party its 51-person majority, out of a total of 100 possible seats.

The party needed to defend every seat possible in order to retain control.

But on Tuesday, two key defeats decisively put the power over the Senate back in Republican hands.

Democratic incumbent Sherrod Brown lost his bid for reelection in the midwestern state of Ohio. Meanwhile, in West Virginia, Republicans picked up a seat formerly held by retiring independent Senator Joe Manchin.

The Republican Party also successfully defended a vulnerable seat in Texas, held by Senator Ted Cruz. Tuesday was Cruz’s second time beating back a Democratic contender angling to take his seat.

Meanwhile, in Nebraska, another Republican incumbent Deb Fischer fended off an upstart challenge from independent candidate Dan Osborn, who made the race a nail-biter in its final weeks.

The shift in control over the Senate could pave the way for Republicans to hold both chambers in Congress, which would give the party power over the legislative agenda for at least the next two years.

More details to come.