Joe Biden will be giving a big speech on the anniversary of January 6th. Its themes could not be more important. And yet, we have every reason to anticipate the media covering it by discussion whether or not it actually helps Trump in the opinion polls for Biden to lay out the stakes in this campaign. It’s what they do. They’ll poll the speech and then spend hours and hours and spill buckets of pixels on whether or not “it works.” Margaret Sullivan explains why that’s wrong and what they should do instead: When Joe Biden talks on Friday about US democracy on the brink, there’s no doubt that it will be a campaign speech. Maybe the most important one of his life. But the speech will be more than that. It’s intended as a warning and a red alert, delivered on the anniversary of the violent January 6 insurrection at the Capitol. The date was chosen for good reason – to make the point that more mayhem and more flagrant disregard for the rule of law and fair elections, are just around the corner if Donald Trump is re-elected. Can the political media in America get that reality across? Or will their addiction to “horserace” coverage prevail? So far, the signs aren’t particularly promising. A line high up in the New York Times’ advance coverage of what Biden plans to say is typical of the mainstream media’s tone and focus: “The two speeches are part of an effort to redirect attention from Mr. Biden’s low…