It wouldn’t be a Democratic convention without a tribute to Ted Kennedy. The party celebrated his life and legacy four years ago in Colorado, where an ailing but determined Kennedy made his last appearance at a national convention.

And they celebrated him again Tuesday night in Charlotte in a clever video tribute that served a second purpose as well. In one arresting montage, it showed Kennedy facing off with Mitt Romney during their 1994 debate at Faneuil Hall. By highlighting Kennedy’s debate accusation that Romney was “multiple-choice” on abortion, it underlined the Republican nominee’s subsequent flip-flop on abortion rights.

It also linked Ted Kennedy and his accomplishments to Barack Obama and his.

And yet, there was an off note as well. The video was introduced by 4th District congressional candidate Joseph P. Kennedy III, son of the unremarkable former Congressman by (almost) the same name.

That gave a coveted evening speaking spot to a candidate who hasn’t yet won the Democratic primary, which takes places on Thursday. True, one of his opponents, Rachel Brown, is a wild-eyed follower of Lyndon LaRouche. Still, the other, engineer Herb Robinson of Newton, is an affable, if underfunded, candidate. Yes, yes, Robinson has little chance of winning. Still, he deserves fairer play from the Democratic Party.

There are, after all, Kennedys aplenty who could have introduced a tribute to the late senator, including his widow, Vicki, and his two sons, Ted Jr. and Patrick.

As for young Joe Kennedy, he may well win election and become a dedicated and effective public official. But that hasn’t happened yet. Right now he seems like a callow candidate trying to capitalize on his famous name. It’s odd for a party that celebrates the success of the average Joe to give this completely unaverage Joe such a high-profile primary-week advantage.