President Joe Biden, his reelection bid imperiled by his own party, defiantly declared Thursday in a press conference-turned-referendum on his candidacy that he is still the “best person” to defeat Donald Trump. In his first solo news conference since November — and with Washington on edge — the 81-year-old Biden forcefully dismissed multiple questions about fellow Democrats declaring that he was no longer up for the rigors of the campaign and should abandon his reelection bid. “If I slow...