The media may well have failed, but it is a stretch to say that fear of reprisals was behind that performance. As these polls in the LA Times archive show, Bush's national approval rating in February 2003 (57 percent) was declining, and was the lowest it had been since he took office. Here is what the Times Poll said about Bush and Iraq after the president tried to rally the nation behind his policies in his State of the Union address:
Iraq and Saddam Hussein: Nearly three out of five Americans approve of the way George W. Bush is handling the situation with Saddam Hussein in Iraq, while 38% disapprove. Virtually all Republicans are solidly behind Bush on this (74% approve strongly), while 59% of Democrats and 63% of self-described liberals disapprove. More men than women also approve (65%, 50% respectively). A majority of Americans (55%) trust that George W. Bush will make the right decision about Iraq. Women are not entirely convinced of that--49% trust him to do the right thing, while 43% don't.That's support, but not overwhelming, certainly not enough to justify a media clampdown out of fear of retribution from the government or the public.
And while those numbers went up, at least briefly, once the war began, that was after the media had supposedly been cowed into submission. So if reporters missed the story, they are going to have to come up with another reason.
The Times Poll from that era, by the way, has some other interesting numbers. After the war began, four out of five respondents said they would consider the invasion a success even if WMD were never found, and 85 percent said the war would be worth it as long as Saddam Hussein were killed or captured.