To play Devils Advocate for a moment: Why do we need, or even want, a newspaper to endorse a President? How does it not undermine a paper's journalistic ethics to be neutral and fair?
I actually agree with you, newspapers really shouldn't be doing this. Our major local paper in the Twin Cities basically torched its reputation by endorsing wildly unqualified candidates for city offices (like, one guy they endorsed for Minneapolis city council didn't even live in Minneapolis). They recently decided to stop doing endorsements at all, which I think is the right decision. But that's not what happened h…
At the national level, I don't think it really makes a difference if a newspaper endorses a candidate for President. Those who read and value the opinions of that newspaper are more inclined to vote for the endorsed candidate anyways.