A late-December flurry of articles on a revival of Bernie Sanders' prospects points to a cardinal rule of political journalism: The story must change. Whether the story has actually changed matters not.

Thus, we had a headline in The New York Times reading, "Why Bernie Sanders Is Tough to Beat," and one in Politico that said, "Democratic Insiders: Bernie Could Win the Nomination." The polls, however, have barely budged.

In a humorous tweet saying, "ThE PriMaRy HaS BeEn A CrAzY UnPrEDiCtAbLe RoLLer CoAsTer RiDe," statistical analyst Nate Silver compared recent RealClearPolitics averages for Joe Biden and Sanders to those of a year ago. On Dec. 19, 2018, Biden was at 27.5 percent and Sanders at 19 percent. Exactly a year later, Biden was at 27.8 percent and Sanders at 19.3 percent.

The first poll after the December debate, Silver tweeted, showed "not a heck of a lot going on." Andrew Yang, Amy Klobuchar and Pete Buttigieg each gained a point. Bernie and Michael Bloomberg lost one.

A FiveThirtyEight/Ipsos poll asked likely Democratic primary voters who won the face-off. Biden got the most votes. Sanders came in second.

Nevertheless, Politico quotes Faiz Shakir, Sanders' campaign manager, saying that political insiders and pundits are finding it harder and harder to ignore Bernie because "he's rising in every average you see." That would seem at odds with reality, but one must concede that 19.3 percent is better than 19.0 percent.

It's true that Sanders wasn't getting a lot of attention in recent months but for two plausible reasons. One is the rise of Elizabeth Warren. The other is his heart attack.

Warren's numbers slipped after other candidates went after her. Sanders, if anything, benefited from being left alone.

Sanders loyalists seem to be ignoring that their candidate suffered a heart attack only three months ago. That Bernie is back campaigning is a tribute to his resolve. And we're pleased to see letters from cardiologists reporting that he is recovering well. But it does not cancel out the seriousness of what happened.

About 1 in 5 people who suffer a heart attack are readmitted to a hospital for a second one within five years, according to the American Heart Association. And a heart attack elevates the risk of a stroke. Sanders is 78.

The Vermont senator's people insist that Biden's lead in the polls will narrow or vanish once backers of Warren come over to their man. It is not clear whether they would in large numbers.

Sanders, not unlike President Donald Trump, has a cultlike following, which means few leave him but also few join up. And while Sanders conceivably could take hard-left support from Warren, Biden could take moderates from Buttigieg, Bloomberg, Klobuchar, Yang and Cory Booker.

Referring to Biden, Sanders recently told The Los Angeles Times that Trump will "eat his lunch." Biden retorted that he will invite Bernie for "dessert" at the White House. Biden does know how to return a punch.

I'd wager that the spate of Bernie-can-win analyses reflects some news sources' sensitivity to complaints that the "corporate media" is slighting Bernie. That and the need for a new political angle every week.

In a replay of 2016, Sanders and his surrogates are portraying the "Democratic establishment" as the great enemy. They need reminding that other Democrats have a right to an opinion. Also, not all Democrats love Bernie's bashing of the leadership or how he slips in and out of the party, reenlisting when an election approaches.

The latest Economist/YouGov poll, meanwhile, shows Biden ahead of Warren by 11 points and ahead of Sanders by 13. As they say, the more things change ...