When the National Enquirer first published a 2007 story on John Edwards’ “shocking mistress scandal,” the mainstream media ignored it, in part because the story was weak and the woman wasn’t named. The same thing happened months later when the tabloid said that Edwards had fathered a love child.

The media could still act as gatekeepers in that pre-Twitter age. It wasn’t until the summer of 2008, when Enquirer photographers got pictures of Rielle Hunter with their baby at the Beverly Hilton Hotel, that he admitted the affair--but not paternity--on “Nightline.” Then the story exploded.

The Enquirer’s rather weak story alleging that Ted Cruz had five extramarital affairs with unnamed women unfolded in dramatically different fashion on Friday—both because of the way the media marketplace has been transformed and the way the Texas senator handled it.

Few seamy stories, no matter how half-baked, can stay bottled up for long in a culture where anyone can post anything on Twitter, Facebook, Instagram or Snapchat—and then have readers demand to know why the press is covering up the alleged scandal.

Cruz, therefore, faced a dilemma. By remaining silent, he ran the risk of allowing those who saw the allegations online to believe he wasn’t contesting them. But by denouncing them as “garbage” in front of the cameras--without being asked--he gave the mainstream media a green light to run with the story. All they had to do was endlessly replay his sound bites.

I have reported extensively on the Enquirer over the years. The supermarket tabloid has plenty of excesses, sometimes makes mistakes and boasts of paying for information. On the other hand, the paper broke significant stories about the O.J. Simpson murder case, the first of Tiger Woods’ many mistresses, and Charlie Sheen having HIV and claiming he was being extorted. And, of course, its reporting on Edwards trying to cover up that he had fathered an out-of-wedlock baby led to a corruption case, which ended after a mistrial.

The latest headlines on the 2016 elections from the biggest name in politics. See Latest Coverage →

But the Cruz piece is an example of a classic Enquirer tactic: sometimes putting out a half-baked story in hopes that sources will come out of the woodwork, attracted by the lure of a big payday, and confirm the sleazy details. The piece quoted unnamed “snitches,” spoke of "rumors" and said "private investigators" were looking into these rumors without identifying who they worked for. There were also blurred photos of the unnamed women.

The Cruz allegations were starting to dribble out on cable news on Friday morning. MSNBC asked its new contributor Rick Tyler, a spokesman fired by Cruz, about the story and Tyler said he didn’t believe it. CNN allowed former Cruz aide turned contributor Amanda Carpenter to be embarrassed when Boston Herald columnist and Trump supporter Adriana Cohen demanded on air that Carpenter deny having had an affair with her former boss (which Carpenter forcefully did). That was terribly unfair and should have been cut sooner.

By denouncing the allegations on camera, Cruz gave the media a green light to run with the story. That’s a difficult dilemma for politicians because staying silent might have been viewed as not challenging the allegations.

Yet Cruz did more than rip the Enquirer story as a “tabloid smear.” He said “it is a smear that has come from Donald Trump and his henchmen.” There is, however, no evidence of that.

Trump said in a statement that he “had absolutely nothing to do with it” and “did not know about it.” In a passive-aggressive postscript, he said that while the tabloid had been “right about O.J. Simpson, John Edwards, and many others, I certainly hope they are not right about Lyin’ Ted Cruz.”

The Enquirer said in a statement that it’s not influenced by anyone other than its editors and reporters. Roger Stone, a former Trump adviser and the only person quoted on the record—as Cruz pointed out—accused the senator of lying about him. Trump is friendly with David Pecker, the parent company’s CEO, and the Enquirer has endorsed him—but neither of those things prove any link to the story.

Cruz’s charge against Trump is the mirror image of the one that Trump hurled against Cruz when a tiny anti-Trump PAC spent $300 on an ad featuring that nude GQ picture of his wife Melania. The senator has nothing to do with that political action committee.

What the Enquirer story is lacking is any account from a woman involved, or emails, texts or photos that would support the explosive allegations against Cruz. Once, that might have been enough to keep news organizations from touching it. But that age is long gone.

This game of smear and counter-smear has dragged the campaign into the gutter—and the media along with it.

Howard Kurtz is a Fox News analyst and the host of "MediaBuzz" (Sundays 11 a.m. and 5 p.m. ET). He is the author of five books and is based in Washington. Follow him at @HowardKurtz. Click here for more information on Howard Kurtz.