The Washington Post planned to endorse Kamala Harris over Donald Trump before owner Jeff Bezos, the Amazon founder, decided again it, the newspaper reported.
I think the laws we already have about free speech mean the government absolutely can't tell a newspaper owner what to print. They can be held liable if they break laws, but not endorsing a candidate is not illegal.
EDIT: If you don't like what I'm saying that's on you. The constitution of the US is pretty clear about this and the Supreme Court has upheld it numerous times. I don't think it's cool that Bezos did this, but I also don't think that a law stopping someone from doing it is a good idea or even plausible in the US. As long as we're run as an oligarchy we'll never get past problems like this, because if there is money to be made off information and money can buy power, unethical people will make unethical moves to manipulate the information that people take in. But as we all know, you cannot legislate morality, so the only thing to do is to remove the incentive.
We absolutely have laws that regulate portions of news coverage. Yeah, they can't tell them what to say or what not to say, but there could exist laws that prevent owners from exerting too much influence over it.