Social media arguments always risk creating the backfire effect: when someone is forced to defend a weak position, rather than admit they are wrong, they are more likely to rise to the moment emotionally, and defend their position in such a way that their conviction is actually strengthened! Arguing is literally counterproductive with such folks.

A much better was is to:
1. First establish a common value (do you both care about the future of America? Do you both believe in decency? Etc. Next, help the other person disengage their sense of self worth from the political position they hold. (Does your neighbor’s mom need to hear what a good mom she is? Do you respect her Christian values? Is she kind?). Acknowledging the self worth of someone helps them be less dependent on their political opinions as vital to their self esteem. That helps make it safer to consider changing their mind.

Only then can you discuss an issue with any hope of creating positive change. And here, it’s better to ask open questions that genuinely seek to understand the other person’s position. In allowing them to explore, for example, the contradictions between their Christian values and Trump’s rape charges and lies.
But you have to ask about it in a way that does not feel like a personal attack.
Not easy - and near impossible over social media!