trek to selma's annual remembrance, but it is his first as president of the united states. and ahead of today's speech, he used the white house's bully pulpit to send a clear message about history. >> it's important to say, from the white house, for the entire country to hear, history matters. history matters. and black history matters. look, i can't just choose to learn what we want to know. we learn what we should know. we have to learn everything. the good, the bad, the truth, and who we are as a nation. >> this is a moment in which black history is under attack. there are those, you know, in the political atmosphere who basically want to say, we should only talk about the good parts and not about the bad parts. not about the fact that john lewis was beaten nearly to the point of death on the edmund pettus bridge, and people who are still alive today were there to witness it.