Yes, we have some influence. Granted, they follow Trump closely, so his failures to them will have the biggest effect on Trump voters.
But we try. It's a big job. Many hate all government (Libertarians), they are beyond help. Well, technically you could get them on small issues such as eminent domain.
But we need to concentrate on Trump voters of the regular kind, working class Americans. We need to show them there are just as many jobs building alternate energy as there is mining coal. They may need to move West, but that is how things are going. Nothing is going to be the same 20 years from now.
What struck me yesterday was that we had all home made signs protesting Trump's Sessions firings.
When you compare that to a Trump rally, the people inside have pre-printed signs. We have those too, but only for those that were not prepared for the protest and just showed up.
MAGA is one sign and the other one Women for Trump. They are responding to Trump telling then that they are a forgotten people. Nobody is representing them. This is true as far as anti-abortion, guns and other traditional right wing causes. But you have to CAPTURE them as far as their views on jobs, taxes, trade etc. You have to explain that most manufacture jobs are not going to come back. This is due to cheap shipping of consumer goods and low wages in Asia. We do in fact make things here, bigger things. Homes. cars, things we use a long time around our homes. Doors, windows, all outside structures.
One aspect of Trumpism will only disappear when Trump gets toxic enough. The economy is OK now, though healthcare takes a big cut. Trump is charismatic enough with his voters that when he repeatedly tells them they are better off, they believe it. When he tells them they are ”safer from foreigners” they believe him. But they still believe The Wall would also be built.
Trump angered the people to show up to vote and spoke in simple terms. The famous picture shows the "he speaks how I feel" phenomenon. Some of that includes patriotism, respect for law and order, military and all that. An implied white Christian world.
What we need is to educate the working classes about the realities of our problems (climate, energy, infrastructure) and that those problems actually mean jobs. Perhaps they are not well educated and cannot express their feelings well (Trump speaks for them, the signs they hold are ready made), but we can fix that with a charismatic leader that explains it and then hands them different signs. They will realize by 2020 that Trump is not going to give them healthcare, for example. Beto or someone like him in 2020 will need to explain both jobs and healthcare and explain that Mexicans are NOT taking their jobs unless they are willing to be roofers and landscapers at minimum wage.
Populist movements run 2-4 years. One task is to explain job wages and all. The other task may work out by itself: Trump is going to be rather toxic by then. Trump has no political views of his own. He is a rather superficial person who wants those around him to "like" him, even though he has the power so those whose jobs depend on it will pretend to like him. They only have some one personal issue (small government, low taxes) that keeps them attached to Trump. The Trump brand has taken over all other viable candidates with right wing views. No other candidate will rise out of the GOP mess in two years. Possibly Nikki Haley if Trump is impeached. Others like Cruz are equally toxic and disliked enough to fail as presidential candidate.