While doing one of my recent posts, I looked at the Gallup report on their question about "trust and confidence in the mass media ... when it comes to reporting the news fully, accurately, and fairly." That report showed changes by party identification*:
The obvious feature is the growth of polarization since the late 1990s--the partisan gap has gone from about 10-15 percentage points to 50-60. I haven't kept a systematic record, but offhand I can't think of any opinion question that's shown a bigger increase in partisan polarization. There are a couple of other things that are worth noting:1. Like Republicans, independents show a clear downward trend. As a result, they are now closer to Republicans than they are to Democrats. In the 1970s and 1990s they were about midway in between Democrats and Republicans--in 2022, they were about three times as far from Democrat as from Republicans. This may be because people (especially people who aren't that interested in politics) tend to react to controversy by concluding you don't know who you can believe. As a result, it's easier to make them lose trust than to gain trust.
2. There is some tendency for people to be more positive about the media when a president of the opposite party is in power. The strongest case is with Trump, when Democratic confidence increased substantially and stayed high while he was in office--it also rose under Bush and declined under Obama. It's harder to tell with Republicans because the trend is so strong, but the decline in trust seemed to slow down or stop under Obama, and there's been a slight increase under Biden. Probably this occurs because the president gets a lot of attention, and news stories tend to focus on negative things, giving supporters of his party more to object to (and opponents more sense that the media is doing its job).
The second point leads to a question about short-term changes in opinion: do the opinions of Democrats and Republicans move together or in opposite directions? One possibility is that there are changes in the general quality of news coverage, and people of all parties react to them in the same way--for example, confidence might have declined as it became clear that many stories about "weapons of mass destruction" in Iraq had been inaccurate. Then the opinions of Democrats and Republicans would move together, even though there would be a persistent difference between them. This would be similar to assessment of current economic conditions--if unemployment or inflation increases, both Democrats and Republicans will rate the economy as worse. Another possibility is that people react according to whether the news reflects well or badly on their side--for example, a negative story about Biden will cause Democrats to lose confidence and Republicans to gain confidence.
To judge this, I computed the change from the previous year. There was one case with a 21-year gap, which I discarded because change over a long period is dominated by the trend, and a few with a two-year gap, which I kept. Comparing changes among Democrats and Republicans:
There is no association (the correlation is -.03), but it's not just noise--some of the individual changes make sense in terms of what was happening then. In 2001 and 2009, supporters of the new president's party lost confidence in the media, and supporters of the other party gained. In 2016, supporters of both parties lost confidence--presumably because of negative coverage of Trump for Republicans, and stories about Clinton's e-mails for Democrats. In 2017, confidence in the media increased substantially among Democrats but also increased a little among Republicans, suggesting that some Republicans had qualms about Trump. The changes among independents had positive correlations with both the changes among Democrats (.50) and Republicans (.21). This pattern suggests that the changes are a mix of consensus and partisan reactions. What if we looked at changes among independents to get a sense of the consensus part? Sampling error has a large impact on those figures, but for what it's worth the biggest positive changes among independents are in 1974, 2017, and 2013; the biggest negative changes are in 2004, 2007, and 2012.
*The question has four possible answers, but the Gallup report collapses that into two, and the recent datasets aren't publicly available.