Donald Trump used to brag that the media couldn't stop him. Now he blames the press for his struggles. (Harrison McClary/Reuters)

Donald Trump can't make up his mind: Is the press weak and its coverage inconsequential? Or is the media so influential that it could keep him out of the White House?

Lately the Republican presidential nominee and his allies have cast the media as the main factor behind his struggles, ascribing tremendous power to the fourth estate.

On ABC's “This Week” Sunday, Trump surrogate former House speaker Newt Gingrich went so far as to say that “without the unending, one-sided assault of the news media, Trump would be beating Hillary by 15 points.”

Just for perspective, Democratic presidential nominee Hillary Clinton leads Trump by six points nationally, according to the RealClearPolitics polling average. So Gingrich is effectively arguing that media bias is responsible for a 21-point swing.

That seems like a lot — especially when you consider that Trump has frequently portrayed the press as a feeble force unable to dent his campaign. When Dr. Oz asked Trump last month how he deals with the stress that might accompany critical coverage, the candidate shrugged.

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“I don't think it matters that much,” Trump said of the media. “In theory, if it mattered, I wouldn't be leading nationally,” he added. “CNN just came up with a poll where I'm up two nationally. ... It's amazing. It doesn't matter as much, like it used to matter.”

For the record, most polls showed Trump trailing at the time of his Sept. 14 interview with TV host. But the race was closer then than it is now, and some polls did show Trump in the lead. Clinton, diagnosed with pneumonia, had staggered out of a 9/11 memorial service three days earlier, and the media narrative was about Trump gaining momentum.

When things were going well, Trump said he was wholly unconcerned by a press corps that “doesn't matter” very much. It was a familiar attitude from a candidate who has often minimized the clout of various news outlets by saying they are “failing,” “dying” or suffering from low ratings and readership.

There are many flaws in Trump's theory about a media conspiracy against him, some of which I covered last week. But one of the biggest problems is that Trump is contradicting himself. After boasting throughout the campaign that the flimsy media can't stop him, he is suddenly trying to convince supporters that the press has the ability to snatch the election from his grasp.

Trump's most loyal backers, who have followed him through many other reversals, likely won't blink at this media flip-flop. But voters bothered by Trump's inconsistency have one more reason to turn away.