He definitely got a boost but at the same time the tensions are increasing in USA. Everyone is blaming everyone these days. I even updated my US Civil War topic in the politics board with new predictions. Things are still not going to be easy when society is being polarized and radicalized like this.
If that is the democratic party's plan then I think it is their worst idea because they are destroying their own country. The United States is committing suicide without the need for competition from other competitors because the consequences of the recent incident will be huge and will cause deep division in the country. Even if Trump receives more support or even his election as president, he will never be able to erase the divisions in the country. Therefore, I personally believe that the act of assassinating Trump was a spontaneous individual action, not the idea of the opposition party.