Clear & Palatable Goals
I think it’s critical for anyone who has Republicans that they love who are reflexively supporting Trump to focus on corruption and alternatives that will truly address corruption. Make it clear that you aren’t arguing that Hillary should have won. Make it clear that you aren’t trying to convince them to vote Democrat, or even take the Libertarian baby step away from the ledge. Just that you want them to acknowledge the Trump is clearly not the answer to our collective problems, and is in fact, making them worse.
I think you’re right on target to point out that political corruption is the common ground that the left and the right have. Common ground is step one in working with any belligerent party. I actually do believe that if a person’s number one concern was this, I can see how potential Bernie voters genuinely became Trump voters, however foolish that may be on other levels. The fundamental difference is that Republicans think that governmental agencies are inherently corrupt, and that businesses are vulnerable innocents being seduced or coerced into corruption by a greedy domineering government. Democrats see business interests as seducing, infiltrating and corrupting government officials, all the while weakening anti-corruption laws to further dominate the process. In the end though, we agree that governmental power + business interests without rules tends toward corruption.
Baby and the Bathwater
When making the case that Trump is not the answer, I think potential issues are also ones where he’s throwing out things they may support, in order to get at things they disagree with. Highlight his ham-fisted, corrupt approach to probelms. Many people are able to deny Climate Change. It’s concrete to the scientific community, but it’s no “hole in the ozone layer” or Cuyahoga River Fire in terms of immediacy or optics. So, an approach of “But Trump is stripping away all environmental protections, including dumping coal debris into rivers” which is some clown-car, old-school style environmental harm of the kind that conservative environmentalists, like hunting groups, can get behind protesting and preventing. The argument here is: “Couldn’t we find someone with a more informed, less corrupt approach to balancing the interests of business and natural resources.” Throwing contraception out with abortion rights fits this model, as does throwing out unemployment protections with the boogeyman of cash assistance. Even Republicans have made a similar arguments to their base about the Muslim ban “like the sentiment, but this was a crazy way to do it…”
Trump is the embodiment of corruption, and has shown himself to be extremely ham-fisted with policy. I get that people thought (for some crazy reason) that he would be the one to end corruption, but instead all he’s done is to go about removing the laws that would define his activities as corruption. Problem solved!
I’m so overwhelmed by all the news, and am a generally scatterbrained person, I can’t start to summarize in a clear and organized way, but the examples of his naked, greedy, self-interested corruption are all there. This seems like it would have to be the wedge. Perhaps once that’s set, and you’ve established that your arguments are a good faith effort to find a common solution, other cracks may begin to appear.