If the political left actually wants to move the United States to the left, they should stop attacking Trump for being a racist and try to work with him. Ignore the crazy stuff he says and look at his actions. He's actually one of the most liberal Republicans in recent history when you examine his policies. He only says outlandish things to garner support from his base because he knows how easy they are to persuade into loyal support.
Trump sets his followers up by saying the most extreme of things, to get the most extreme of the supporters on his side. Because they are the most persuadable, they will literally believe anything he says if he appeals to their base emotions of patriotism, nationalism, and xenophobia. Then he has them where he can say just about anything—including more liberal things—and they'll support it because they trust him. Trump is the first US president to be elected on open support of gay marriage—and his conservative base has accepted gay marriage as well.
Trump’s persuasion is a form of public hypnosis, but he’s only targeting one half of the country—the conservative right. Perhaps because they are magical thinkers who genuinely believe in religion, they are more susceptible to hypnosis. Though the left is equally prone to hypnosis if you appeal to their base emotions of equality and justice. Just look at the Black Lives Matter movement that has persuaded people into thinking there is a rampant white nationalist race war hunting black people in the streets.
Now that Trump has his conservative base under hypnosis—that is they support him, knowing he’s on “their side”—he can say something liberal like, “I support the gays, let them marry if they want to.” Or “The war in Iraq was a mistake, let’s bring the troops home.” And his “conservative” base will agree with him. He could also say, “Maybe marijuana isn't so bad and should be legalized,” and his base will fall in line and agree.
The left can actually get some progressive things done (such as ending foreign wars and the war on drugs) during the Trump presidency if they stop fighting him and actually try to work with him. Sure, Trump says some wild stuff that could be construed as racist, but remember why he's doing it: to hypnotize the right. Ignore his rhetoric and look at his actions. The left is still outraged that Trump said he would build a wall, but he has not built a wall.
Trump is not that stupid, crazy, or racist. Perhaps he's just smart enough to realize that acting stupid, crazy, and racist is the best way to make stupid, crazy, and racist people in America less stupid, crazy, and racist. Trump has his base hypnotized. He can convince the conservative right to become more liberal, if only the supposedly “liberal” left would let him.