This week on "Face the Nation with Margaret Brennan," the U.S. faces some tough questions on public health — and public safety. Americans are gathering for the holidays, some for the first time in years, but health officials are warning a pandemic-weary populace of the dangers posed by a triple threat of respiratory viruses. We'll talk to Dr. Anthony Fauci about the risk. Plus, Rep. James Clyburn and Colorado Gov. Jared Polis.