OPINION: At the House Democrats’ 2019 impeachment inquiry into then-President Donald Trump, Rep. Adam Schiff blocked Republicans from calling witnesses and obtaining documents that could have told today’s unfolding, seedy story of the Biden family in Ukraine. Mr. Schiff, the California Democrat who proudly championed the 2016 anti-Trump hoax dossier, kept the Biden family safe so that Joe could run for president untainted by scandal. House Democrats subsequently voted to impeach Mr. Trump because of a July 25, 2019, phone call he conducted with Ukrainian President Volodymyr Zelenskyy. He asked Mr. Zelenskyy to look into what the Biden duo, former...