>> i'm alley velshi in for lawrence o'donnell. the president is condemning the horrific terrorist attack in new zealand, where a white supremacist killed 49 people in an attack targeting muslims. the killings are sparking a worldwide discussion about islamophobia, but they have also brought attention to the words of our president. political scientist brian class writes in "the washington post" that, quote, trump is an islamophobic bigot. brian will join us to talk about his piece later and the hour and we'll have a live report from the southern border from nbc's cal perry who is going to give us the facts about a situation that donald trump often seems to misrepresent. but first, a day after the president's own party revolted and voted to end his national emergency declaration at the southern border, donald trump did something he's never done before. he issued his first ever presidential veto today in order to block that congressional resolution. the president was forced into that position because 12 republican senators, these 12,