The traditional White House portrait unveiling may be skipped for the first time in decades amid bad blood between Trump and Obama. WASHINGTON — It’s been a White House tradition for decades: A first-term president hosts a ceremony in the East Room for the unveiling of the official portrait of his immediate predecessor that will hang in the halls of the White House for posterity. Republican presidents have done it for Democratic presidents, and vice versa — even when one of them ascended to the White House by defeating or sharply criticizing the other. “We may have our differences politically,”...