Your white friend says the N word, and you say nothing. Your friend tweets about how #BlueLivesMatter or #AllLivesMatter, and you say nothing. Well it's time for it to stop.
I know it can be hard to speak up and say something, especially when it's a friend. But real friends don't let friends say or do racist things. Real friends educate and teach each other. If you have a discussion with your friends about their racist actions and they get defensive and continue to do those things, maybe you should choose different friends. On the other side, if you don't feel comfortable having a discussion with your friends about racism, maybe you should look internally first and think about why not.
"They don't mean it! They're not really racist!" you might say. But while a few offensive words and actions don't equal a KKK member, there is still casual racism. Casual racism includes, but is not limited to: saying racial slurs, supporting the confederate flag, telling racist jokes, saying they'd "never" date anyone of color, ignoring police brutality and the Black Lives Matter movement, and enforcing stereotypes about people of color. All these things may seem small to you, but they have a big, negative impact on people of color.
Sometimes people are uneducated so that's why they do something racist. Educate them! There's nothing wrong with spreading the knowledge you have with others. Many times I have educated my friends on why what they're doing is wrong and they have stopped doing it. You may feel like you don't have the knowledge you need to educate your friends or that you can't articulate your points well. In that case, send them an article that explains it for you. There's plenty of resources to help you out.
If someone is a true friend, they'll at least attempt to see where you're coming from, and they won't end your friendship over this. If you're truly scared that telling someone that their actions are racist will result in the end of your friendship, you shouldn't be friends with that person anyway.