I live in the freak Peoples Democratic State of Maryland. Ive learned, as have many others, that to put something like a Trump sticker on your car is to invite SIGNIFICANT vandalism.
California was like that, too. I was even a little afraid to put a Marines magnet on the back of the car, but I did anyway. Happily no vandalism because of the magnet. But you never know.
So wait until a leftist parks his car and then go attach a Trump sticker to it.
I live in DC and have the same reservation. I'm about to the point that I want to get Trump or other Republican, conservative or pro-life stickers and very neatly place them on top of Democrat/leftist stickers on, especially, new and expensive cars. Let the liberals be vandalized by their own.
I would not put a sticker on a car that wasn't already sporting one, even if I knew the driver's politics. But liberals feel free to deface our signage. If someone has made his bumper a billboard, turnabout is fair play.