Whatever one thinks of Donald Trump and his supporters, nothing justifies the shameful display of intimidating behavior by protesters on Friday, when the Republican presidential nominee held a closed-door fundraiser at the Minneapolis Convention Center.

Videos from that night show protesters spitting, yelling, screaming obscenities and physically crowding in on those attempting to enter the event. Shockingly, there appeared to be little protection available for attendees. Minneapolis police say they did provide some escorts at the end of the night, after Trump had left, but acknowledged that some attendees had to leave without escorts and were the subject of “intimidation and abuse.” There were no arrests, but police say they are continuing to investigate.

This page has been blunt in calling out the behavior of some Trump supporters at rallies — their abuse of protesters and the sometimes overtly racist language on display — as well as the behavior of the candidate himself, who has been only too happy at some rallies to instigate thuggish behavior, even urging supporters to throw out protesters.

None of that excuses what happened Friday night. Protesters were beating on the glass doors of the Convention Center, jostling, shoving and even punching those attempting to enter the event. They vandalized property with spray paint and shouted threats to attendees.

The Minnesota Republican Party has questioned why police were not out in greater force and why protesters were allowed to get so close. Given the controversial nature of Trump’s campaign and previous violent incidents at his events, that is a fair question and deserves an answer.

Freedom of speech is a cherished American right, but it does not extend to mob behavior. There are weeks to go yet in a presidential contest that so far seems to have brought out the worst in both sides. One of these two candidates will be president, and if this republic is to continue its long tradition of a peaceful passage of power, one side is going to have to accept defeat and allow a new president and administration to govern.

That will require restraint, and it wouldn’t hurt to start practicing now. The best way to register disapproval of a candidate is to vote and organize others to do the same. In the end, it’s the only action that will matter.