Mr. Barron currently is a member of the City Council, where his despicable rhetoric, we are happy to note, has had no visible impact on public policy and civic life. Yes, he embarrassed the city a decade ago when he escorted Zimbabwe dictator Robert Mugabe, a serial violator of human rights, into the Council chambers and proclaimed him to be a “bold African man willing to stand up to the world for his people.” But that episode did no permanent damage to the city’s reputation—indeed, it gave New Yorkers a wonderful opportunity to show their contempt for Mr. Mugabe. Mr. Barron, on the other hand, was exposed as a vicious hatemonger.

Mr. Barron’s time in the Council is drawing to a close, thanks to term limits. But he may not be done. Mr. Barron is running for Congress in the Brooklyn district currently represented by Edolphus Towns, who is retiring. With less than a week before the Democratic primary, Mr. Barron is thought to be in a close battle with Hakeem S. Jeffries, who is seeking promotion from the state Assembly.

To their ever-lasting disgrace, Mr. Towns and the city’s largest public-employee union, District Council 37, have endorsed Mr. Barron. That’s why many observers fear that Mr. Barron might well capture the nomination, which is tantamount to victory in heavily Democratic Brooklyn, next Tuesday.

One person could stand in the way of Mr. Barron’s ambitions. President Obama can and should intervene on behalf of Mr. Jeffries. The president doesn’t have to say a word about Mr. Barron, a fellow Democrat, although it would be nice if he called out the councilman for his horrendous rhetoric. A presidential endorsement of Mr. Jeffries certainly would be a blow for the haters, racial arsonists, and refugees from the 1960s who support Mr. Barron’s candidacy.

The district’s registered Democrats will, of course, have the final say. But the party’s leaders at the local and the federal level ought to make it clear that Mr. Barron will be a pariah if he is dispatched to Washington—if a portion of the district’s voters are looking to send some kind of message to the establishment, well, they’ve rallied behind a flawed messenger.

If Mr. Barron wins, he will have a national forum for his hate-filled rants. To be sure, he will be incapable of turning his views into legislation, but still—he will have greater access to the media and a bigger audience for his insulting rhetoric. And here’s the worst part: He’ll be identified as a Democrat from New York.

Is that what Democrats want? Is that what New York deserves?

Those are questions Mr. Obama should ponder in the next few days.

As a result of District Council 37’s short-sightedness, some 672 people are out of work. They received layoff notices a few days ago. Schools Chancellor Dennis Walcott expressed his sorrow over the plight of the laid-off workers, but he made it clear that the union was not so sympathetic. Had its leaders tried harder to find other savings, the layoffs would not have been necessary.

The good news, if there is any, is that the jobs should not affect classroom instruction. Class sizes will not grow. Instructional aides will continue to lend an invaluable helping hand, especially for students with special needs.

The jobs that will be lost may have served a purpose, but they do not seem especially critical to learning and critical thinking. Positions such as “parent coordinator,” “family assistant” and “community associate” actually sound somewhat superfluous to the important work that takes place inside the classroom. One such worker told The New York Times that her job as a community associate was important because students “need people in their school building that look like them and identify with them from a positive standpoint.”

Perhaps there is evidence that student performance improves when children see adults in their schools who share their racial or ethnic background. But that argues for a more diverse teaching staff, not the creation of a new layer of support staff with hazy job descriptions.

Still, whatever the merits of these positions, those who held them would have continued to have them had their union been more flexible. The chancellor understands that sad fact. The union, of course, does not.