Former San Antonio Mayor Julian Castro recalls experience being vetted as potential VP

With Democratic Presidential nominee Kamala Harris expected to make her running-mate pick as early as Tuesday, former San Antonio Mayor Julian Castro took to social media to speak candidly about his involvement in the vice presidential vetting process for 2016. "It's a grind of a process" Castro tweeted Monday. "Candidates had to answer a 150+ question background questionnaire that delved into political, employment, legal, financial and personal family history."