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

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

Marsters used the Internet to publish his hope that someone “shoot” President Barack 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 let his opposition to the president’s policies spill over into hateful rhetoric, but this time it got the attention of federal authorities, who are investigating whether Marsters crossed a line and actually threatened Obama’s life.

Marsters says that he did not, but even if that’s true, his comments were so outrageous that they demand a loud and vigorous response.

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

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

Tonight, the board of selectmen is meeting to consider what the response should be, including possible removal of Marsters from the four town commissions on which he serves. Voters will be able to express their opinions about Marsters if he goes ahead with his plan to run for selectman later this year.

It would be easy to ignore his words as the meaningless ranting of a pathetic crank. It would be easy to say that Marsters’ views about national politics have little relevance to his work on the charter commission or budget committee. Some might even say that it’s wrong to silence Marsters, who has a right to free speech regardless of whether we agree with him.

His words, however, should not be ignored. The antidote to Marsters’ remarks is more speech, and people who don’t speak against Marsters risk leaving the impression that more people agree with him than really do.

And speaking up is not just a job for the people of Sabattus.

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.