The comments by Michael Daniel, who served as White House “cyber security coordinator” between 2012 and January of last year, provided his first public confirmation of a much-discussed passage in the book, “Russian Roulette: The Inside Story of Putin’s War on America and the Election of Donald Trump,” That conclusion was reinforced Wednesday by another witness, Victoria Nuland, who served as assistant secretary of state for Europe during the Obama administration. She told the panel that she had been briefed as early as December 2015 about the hacking of the Democratic National Committee — long before senior Daniel Prieto, recounted a staff meeting shortly after the cyber coordinator was ordered by Susan Rice, President Obama’s national security adviser, to stop his efforts and “stand down.” This order was in part because Rice feared the options would leak and “box the president in.” DNC officials were aware of it — and that the intrusion had all the hallmarks of a Russian operation.