In my ongoing (probably tiresome) campaign to take out every last defense for lesser evil voting, I have heard many say that a populist-talking candidate like Sanders will be responsive to social movements, that he can be poked & prodded & pressured to do the right thing as president.
Here you gotta listen to your elders. Let me play the senior card. Our generation came of age in the era of Nixon who was POTUS from 1969 to 1974, the height of antiwar activity in this country. He was a lot more reactionary & bullheaded than Sanders but he was poked, prodded, & pressured up the wazoo by the antiwar movement. In April 1971, there were over a million people just in Washington, DC to oppose the war. (I’ll never forget it because of the naked man in a see-through raincoat & the million other people.)
The most effective way to influence presidents or Supreme Court justices is to build powerful, massive, democratic social movements. Scares the bejeezus out of them; makes them do the right thing.