What did Donald Trump do today?

He said that white nationalism isn't a real threat.

Yesterday, a self-described white nationalist from Australia shot and killed 49 people in two mosques in Christchurch, New Zealand. Trump initially hesitated to call the attack terrorism, and during an Oval Office appearance before reporters, he had this exchange:

Q: Do you see today white nationalism as a rising threat around the world?

TRUMP: I don’t really. I think it’s a small group of people that have very, very serious problems. I guess if you look at what happened in New Zealand perhaps that’s the case. I don’t know enough about it yet. They’re just learning about the person and the people involved.

In reality, as both the FBI and watchdog groups have noted, hate crimes and membership in white nationalist groups have increased sharply in recent years.

By the time Trump spoke, the killer's political leanings were known worldwide. It's not clear what further information Trump was waiting for in order to understand the shooter, who talked about white nationalism during his internet livestream of the murders he committed at two mosques.

To be clear, there's no reason to think that Trump approved of the killings. But Trump, who was cited by the New Zealand killer as a white nationalist role model, has always shown a real fear of confronting or speaking ill of the white nationalists he believes are an important part of his base.

For example, even after it ended in murder, he famously broke free of his own staff's attempts to restrain him from declaring the white nationalist rally in Charlottesville to be the work of "very fine people." He blamed the victims of a mass murder at a Jewish synagogue in Pittsburgh rather than comment on the white nationalist ideology of the killer. His White House compiled a list of terrorist incidents that left off attacks against non-white and non-Western targets. Trump is a vocal supporter of Alex Jones, who says that the world is undergoing a "white genocide" (a phrase also used by the New Zealand shooter). He's retweeted hoax videos from white nationalist groups, and pardoned a convicted felon who was a darling of the white nationalist movement.

Trump did not use the word "Muslim" in any of his comments on the shooting today. His reluctance to note that Muslims peacefully engaging in worship were the victims also has political roots: he has built his political brand on the belief that his own supporters hate Muslims.

Why does this matter?

• A president who can't easily condemn racially motivated murder can't do the work of the presidency.

• People who voted for Trump who aren't Islamophobic, racists, or white supremacists, might not like that he apparently thinks they are.=

• Ignoring politically inconvenient problems doesn't make them go away.