Story highlights Both political parties chose their leaders in the Senate on Wednesday

Democrats also formally added Vermont independent Bernie Sanders to their ranks

Washington (CNN) Republicans re-elected Mitch McConnell as Senate majority leader Wednesday while Democrats tapped Chuck Schumer as their leader as both sides prepare for critical battles with the incoming Trump administration.

"Last Tuesday night was something none of us expected," Schumer said Wednesday. "When you lose an election like this, you can't flinch, you can't ignore it. You need to look it right in the eye and ask, 'Why?' Analyze it and learn from it.'"

As part of that post-election analysis, Schumer formally added top liberal lawmakers -- Sen. Bernie Sanders and Sen. Elizabeth Warren -- to the ranks of leadership. But he also added Sen. Joe Manchin, a conservative West Virginia Democrat who is one of many Democrats facing perilous re-election bids in just two years.

Sen. Amy Klobuchar, D-Minnesota, said expanding the ranks of Democratic leadership to span the ideology of the party from Sanders to the more conservative Manchin was important to rebuilding the party and its message.

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