Democrats are hopeful again. Party leaders on Wednesday celebrated big wins up and down the ballot across deep-blue New York and California to swing-states Georgia, Pennsylvania and Virginia. There were signs that key voting groups, including young people, Black voters and Latinos who shifted toward President Donald Trump’s Republican Party just a year ago, may be shifting back. And Democrats across the political spectrum coalesced behind a simple message focused on Trump’s failure to address rising costs and everyday kitchen table issues. But just beneath the party’s relief at securing its first big electoral wins since last November’s drubbing lay unresolved questions about its direction heading into next year’s midterm elections.