TREVOR HUNNICUTT and JEFF MASON U.S. President Joe Biden, who declared optimism about the midterm elections this week despite opinion polls predicting Republican wins, had reason to feel vindicated morning even though his Democrats could still lose control of Congress. Republicans may eke out a narrow majority in the House of Representatives and the Senate was still up for grabs with key races in Arizona, Georgia and Nevada undecided. But that was all part of better-than-expected news for the White House. Democrats bucked dire forecasts in national races, clinched governors' races in states seen as crucial to the next election in 2024,…