Donald Trump, 2016 Republican presidential nominee, left, shakes hands with Mike Pence, 2016 Republican vice presidential nominee, during a campaign event at Youngstown State University in Youngstown, Ohio, U.S., on Monday, Aug. 15, 2016. Trump&amp;#39;s plan to prevent terrorist attacks on American soil includes a screening test meant to allow entrance only to immigrants &amp;quot;who we expect to flourish in our country.&amp;quot; Photographer: Ty Wright/Bloomberg via Getty Images