Once again we're hearing rumors of a Joe Biden presidential run. First Read, Chuck Todd's inside-skinny corner at NBCNews.com, suggests that this might be excellent news for Hillary Clinton. He and his crew offer two reasons, the first of which is actually somewhat plausible:

First, it would force Clinton and her campaign to step up their game. "She's a terrible front-runner but she's a marvelous candidate when she gets into the middle of the race," as NBC/WSJ co-pollster Peter Hart (D) put it on "Meet the Press" yesterday. In other words, give her a real Democratic race -- a la what she experienced in the spring of 2008 when Clinton trailed Barack Obama -- and it'll force her to be a stronger candidate.

I wrote in July that Clinton campaigned best in 2000 when her opponent in her Senate race, Rick Lazio, attacked her, and she rallied, of course, in the latter part of the 2008 presidential race, even though she fell short of a win. So maybe she needs a challenge she takes seriously.

But the second reason a Biden run is supposed to be good for Hillary strains credulity:

Two, Biden jumping in would swap the scandal-focused coverage of Clinton and replace it with horserace-focused coverage. It has become increasingly apparent that Hillary Clinton might not be able to beat a unified political press corps on constant scandal patrol. But she could beat Joe Biden and Bernie Sanders.

It's nice of Todd & Co. to acknowledge that the press is actually working to defeat Clinton. But why would that stop if Biden gets into the race? The press is already writing both types of stories -- stories about the email saga and stories about Clinton's battle to win what was supposed to be an easy race -- with just Sanders in the race as a major challenger. (Look at his crowds! Look at his poll numbers in New Hampshire!) The coverage isn't going to switch to all-horserace if Biden gets in -- the GOP and its many loose-tongued email-saga leakers will see to that. Clinton's difficulties won't change. They'll add up.

But she may still retain a lead, perhaps because far fewer real Americans care about the scandals than we think, perhaps because she'll find her voice on the campaign trail, perhaps because neither nor Sanders or Biden is a strong enough candidate to beat her. We have no idea. But no, a Biden candidacy is not going to change the press coverage of Clinton. It'll remain relentlessly negative, because this year the press is determined to take Clinton down.