Because an incredibly large amount of people demand a citation for the absurdly obvious as a trolling tactic, such as writing "cite something!" as their response to the obvious statement, "The sun provides light", I assumed you were doing so as well.
However, I will give you the benefit of the doubt and assume you are one of the few people to make such a request without being trolls.
Look up current coronavirus death toll and projected death tolls in the United States.
Look up the way the Trump WH dismantled the CDC, thereby making American citizens vulnerable to the coronavirus, and look up the ways in which Trump's stream of misinformation about both the coronavirus and the government response to it has endangered Americans.
Then look up the impact Trump's decisions have had on those suspected of illegal immigration, those applying to the U.S. for sanctuary, and those who have otherwise sought legal immigration to the United States.
Finally, look up the death threats made by those who claim that Trump is their man and whom Trump has refused to condemn.
You should find all the evidence you need.
Now, a voter is not responsible if his or her candidate lied and turned around and did terrible things the voter could not imagine.
But at this point, it is simply no longer possible for any sane human being to remain unaware of the harm Trump has done, and therefore to continue to support Trump is possible only if one approves of the harm Trump has done as well. This is simple logic.