The 50th anniversary of the March on Washington and Martin Luther King’s “I Have a Dream” speech has been a welcome reminder of how far we have come on our journey as a nation committed to equality and justice.

The ugly comments by Sabattus town volunteer David Marsters are a shocking reminder of how far we still have to go.

Marsters used the Internet to publish his hope that someone “shoot” President Obama, to whom he referred with a racial slur that sounds more at home in the Jim Crow-era South than 21st-century Maine. It’s not the first time Marsters has let his opposition to the president’s policies spill over into hateful rhetoric, but this time it’s gotten the attention of federal authorities, who are investigating whether Marsters crossed a line and was actually threatening Obama’s life.

Marsters says that he was not, but even if that’s true, his comments were so outrageous that they demand a loud and vigorous response. Maine should not tolerate this level of barbarism.

Fortunately, the town of Sabattus is responding as it should. Town Manager Andrew Gilmore issued a strongly worded statement Tuesday, as did Androscoggin County Sheriff Guy Desjardins, a Sabattus resident.

He said that Marsters does not represent the town. “We’re better than that,” he declared.

Thursday night, the Board of Selectmen is meeting to consider what the response should be, possibly removing Marsters from the four town commissions on which he serves. Voters will get their chance to have their say if Marsters goes ahead with his plan to run for selectman later this year.

It would be easy to ignore these words as the meaningless ranting of a pathetic crank who likes to be the center of attention. It would be easy to say that Marsters’ views on national politics have little relevance to his work on the town charter commission or budget committee. Some may even say that it’s wrong to silence Marsters, who has a right to free speech.

But this is not something that should be ignored. The antidote to speech like this is more speech, and people who don’t speak against Marsters risk leaving the impression that there are more people who agree with him than there really are. And speaking up is not just a job for the people of Sabattus.

Just like Gov. LePage’s reported comments about President Obama’s race, this outburst is getting national attention and it influences how people around the country think of Maine. It’s incumbent on all of us who are appalled by Marsters’ words to say so and make clear that — regardless of where we stand politically — this man does not speak for us.