Last Monday evening, as President Trump discussed expanding American military presence in Afghanistan, the Johnson family gathered for pizza on the porch outside their home in Novato. Nineteen-year-old Holten and Sawyer, 18, recalled memories of playing football for Casa Grande High School (“He threw his first touchdown to me,” Sawyer said of his older brother), while their mother, Darby, looked on with equal doses of pride and trepidation. The family wes just notified a few…