Swastikas. Black face and Confederate flags. Calls to “go back where you came from.” Chants of “build that wall” in front of Latino schoolchildren. Spray-painted messages saying “Kill all niggers.”

People participating in the annual Muslim Day Parade carry U.S. flags in the Manhattan borough of New York City, September 25, 2016. 

Since Donald Trump won the United States presidential election on Tuesday, social media has been full of such hateful messages and images, some of which come from people who identify as Trump supporters. People have reported being targets of aggressive comments and vandalism based on their perceived race, ethnicity, religion, or gender. News outlets have also reported on racist graffiti and a physical attack on a female Muslim college student – incidents that authorities say they are investigating.

While all these cases haven’t been verified (and one is reported to have been false), the sheer number of allegations of discriminatory violence and other acts, and the overt examples shared on Twitter and Facebook, are a cause for concern – and action.

Such bias attacks are not new of course. Hate crimes against American Muslims were already sharply on the rise in the US before the election, according to one study. Social media has long had examples of hateful speech. We also don’t have hard data on hate crimes during the campaign, or over the last few days (the FBI has yet to release its latest data on hate crimes).

But we have already seen in Britain how the xenophobic and racist rhetoric surrounding the Brexit referendum seems to have turned into a spate of hate crimes after the vote.  It’s not a model to be repeated in the US. Government authorities at all levels need to be responding to acts that threaten violence and discrimination.

President-elect Trump promised to be a president for all Americans. He also promised to make America safe. He now has a chance to live up to those commitments. He should speak out. Call on all Americans to respect their neighbors, whoever they may be. Say that violence and hate crimes are unacceptable and will be prosecuted under his administration. Say that racist, sexist epithets and bullying are wrong. Make clear that he does not stand for hatred. He should not allow some Americans to harm others – whatever their reason.