Although they did not ultimately win all three seats that they needed because of the loss to Alberta Darling last night, they did gain something quite important. They have exactly the number of votes to block and/or undo extreme measures like the Walker Union Stripping Bill because that measure only passed originally by two votes, not three.
And this is why.
The reason why is Republican State Sen. Dale Schutlz who is a Swing Vote who has often opposed the Walker Agenda.
He voted Against the Union Stripping Bill and has also opposed other radical measures pushed through the WI Senate by Walker and his minions like Alberta Darling. So although Dems don't have the Majority Leader position, they may indeed have the Majority of the Actual Votes on controversial issues.