I remember the Twitter stans for Kamala going off after she resigned. She had a bunch of radicalized supporters because she was a black woman, so they could push two angles. Her biggest downfall was Tulsi. That women tore apart her entire platform apart when bringing up her past, so many Twitter users quickly took to ranting about how Tulsi is evil and hates blacks as a result.
I would say supporters are equally to blame. Most joined the Trump side due to crazy internet hijinks of 2013 with the rise of modern Tumblr/Twitter feminism, that then lead into BLM and other groups. When Donald ran, we were at a height of political discourse, which carried him greatly, probably even more so than failed politicians. It seemed like a vast majority did not care for politics in 2010, but after having it shoved into their escapism and daily life so that they feel bad for being a part of “the problem,” I think it got many interested.
As for Russia and China, they pretty much crept up after the election. Russia is really only brought up as an escape-goat for Dems. Hillary was trying to stir up conflict during her run, and once she lost it was easy to say Russia did everything instead of seeing that the actions of Dems were the problem. China is an even more modern threat mostly due to how everything is going. Censorship from the left is now getting confused for the doings of China a lot of the time, as the two seem to think the same. It also does not help that China has a stronghold on media, and gives a free pass to promote Liberal stuff as lost money can be made up with China’s more that 50% in purchases. Of course, the biggest reason why China is due to the protests and America’s response, with a bit of Trump’s trade war mixed in. The fact that most American media seems to neglect the crazy stuff going on down there, if not outright censor it, is a big problem. This in affect, fuels Trump’s policy’s of going against them.
These two will likely have more of a place this election as I can see China propelling Trump higher in electability. He wants to go up against a big nation that many are starting to see huge issues with. As for Russia, I am certain it will and is being used to promote that Trump cheated so the left can gain more followers.
I guess in saying all this, I do not believe one thing can be pinned as the main cause. The ideologies of today and issues seem to have been created by long streams of random events, some seemingly minuscule, that trailed off into much grander issues. I think the random radicalization were a big player in the previous election and I am guessing that foreign nations will take a bigger place in this one, along with the two reasons previously mentioned.