When I took Poli Sci as an undergrad.... the prof was obviously a socialist/communist... but he often warned of a "one-party state" especially where the press is in the "pocket" of that party.
We have that in California. The Republican Party is alive but too small to make ANY difference in State issues (there are a handful to Republican congressmen sent to Washington). Every state-wide office is held by a Democrat, and in every case, a radical leftist Democrat. The Democrats have such a wide majority in both houses that the Republicans are just wasting space. And yes, the Press here is all run by uber-liberal democrats. The only hold out is in Fresno... the San Diego Newspaper USED to be fairly balanced but it was bought out by the LA Times. The Press is the mouth piece of the Democratic Party. And the state judges are appointed by increasingly liberal politicians and so nearly all are now uber-liberal.
What happens in a one-party government where the Press simply speaks for it? The party becomes more and more radical..... and in time, becomes corrupt (becoming a machine). We are seeing the first, the second will come. Look at Chicago or Detroit for decades..... It tends to self-perpetuate, too..... that one party getting stronger and stronger, eliminating opposition by controlling districts, voting policies, etc., etc. For example, it helps the Dems if illegal aliens vote so the Dems created a policy where ANYONE can get a license and when you get a license, you are registered to vote, thus illegal aliens can vote here. And the Dems have workers that go into areas where illegal aliens live and because of VERY loose "mail ballot" rules they've put in place, the operatives just gather up the ballots and vote for them. What can the Republicans do? NOTHING. They have no power and no voice. Oh.... and the Dems got it so your party is listed on the mail in ballot and guess which voter's ballots are often found to be "invalid?" They don't have to know how you voted, they know your party. And all this WILL get much worse....
How can this end? It's hard. But sometimes the one-party government becomes SO corrupt that the Press can't hide or spin it.... and the voters rebel in enough numbers that the one-party can't stop it. In other words, it has to self-destruct. Less often, it becomes SO radical that a popularist movement starts and again votes in numbers too great to manage. Another possibility: The One Party may split and go to war with itself; we're already seeing a "new crop" of uber-liberal communist Democrats in CA and on the Federal level.... the liberals vs. uber-liberals may not be friends for long. We may end up with two parties again, but both leftist but at least some sense of keeping each other theoretically accountable.
Democracy DEPENDS on an open, unbiased press AND on opposing voices being present and heard. There are places in the USA where this exists, I hope, but not in my State. Where you have 90% plus of working journalists admitting to being "liberal" and 95% registered democrats, well.... BUT I HAVE HOPE. Mostly because of the Internet and because the Press is quickly loosing the trust and respect it once had. In some ways, I think Trump may be part of a rising popular rebellion.... kind of scary (rebellions are usually like that) but MAYBE.....
.
