It’s a wonder that President Trump devotes so much time to discrediting the press, when the press does so much to discredit itself.

The media’s errors over the last week haven’t been marginal or coincidental, but involved blockbuster reports on one of the most dominating stories of the last year — Robert Mueller’s Russia investigation. And they all slanted one way — namely, toward lurid conclusions about the Trump campaign’s alleged collusion with the Russians.

Every media outlet makes mistakes. It’s easier than ever to run with fragmentary or dubious information in a frenzied news cycle that never stops.

But underlying the media blunders was an assumption — not based on any evidence we’ve yet seen — of Trump guilt in the Russia matter. This was news, in other words, too anti-Trump to check.

On the day it broke that Michael Flynn had pleaded guilty to lying to the FBI, Brian Ross of ABC News had a seemingly epic scoop. He reported that Flynn would testify that Trump directed him to make contact with Russian officials prior to the election. This was the collusion equivalent of a four-alarm fire.

A New York Times columnist tweeted, “President Pence, here we come.” The stock market dropped several hundred points.

Then Ross “clarified” the story to say that Trump instructed Flynn to reach out to the Russians after the election. This wasn’t a minor detail of chronology; it ripped the heart out of the story. Ross’ blockbuster went from a suggestion of collusion to a suggestion of the normal course of business during a presidential transition. ABC suspended Ross for a month.

CNN followed this up with its own botched report on how Don Trump Jr. allegedly got a heads-up email prior to the release of a batch of WikiLeaks emails during the campaign. The item rocketed around the internet — accompanied by explosive imagery — and was repeated by other major news organizations.

The only problem is CNN flubbed the date. The email came after the release of the documents, not before. Once again, supposed evidence of collusion evaporated upon contact with better-informed follow-up reporting. CNN corrected its dispatch and one of its correspondents called the episode “a black eye.”

Around the same time, Bloom­berg reported that Mueller had subpoenaed Trump records from Deutschebank, before clarifying to say that Mueller had subpoenaed people related to Trump, perhaps Paul Manafort.

A Mueller move that would have crossed a Trump “red line” against investigation of his finances — risking a constitutional showdown — had become something more ambiguous.

If the press had less faith that Mueller is on the verge of bringing the Trump presidency to its knees, it might exercise a little more discrimination. When your only frame of reference for the Mueller investigation is Watergate, everything looks like a proverbial smoking gun.

When for professional reasons (the story of the century) and perhaps partisan ones (a hated Republican kicked out of the office) you’re rooting for the worst, you let your guard down.

Needless to say, the errors in the Russia reporting are a bonanza for Trump. The worse the reporting is, the better for his campaign to brand the mainstream media Fake News . He’d be happy if an outlet of the mainstream media tanked the markets with a flagrantly wrong dispatch every day.

It must be galling for journalists that every mistake they make is amplified into a national scandal by the president, while Trump is willfully careless about facts himself. It must be infuriating to be berated as Fake News, when the White House tried to obfuscate the truth about a Don Jr. meeting with Russians during the campaign, uncovered by good, dogged reporting.

But none of this is going to change. The press can work even harder to exhibit fairness and accuracy under Trump’s withering fire. Or it can play to type. The last week is more evidence that it prefers the latter option, to its own institutional detriment.

Twitter: @RichLowry