I'd like to add a different perspective on some of those issues. I'm from Europe - Poland, specifically - and in my country, we have a few things that Bernie seems to be proposing, namely, single-payer healthcare and government-sponsored universities. I can't comment on stuff like gun laws (those are pretty much totally banned here) and our drug policy is similar to American, so no different perspective here.

So, to get the elephant out of the room, single-payer healthcare is a disaster here. In theory, it seems great, but we have waiting times for some procedures going over ten years (yes, ten years and more), with the most problematic examples being hip surgery, if I remember correctly. Endocrinologists are so scarce that waiting times are in months even in the best circumstances. It is routine to wait for 10 hours or more in the emergency room before somebody takes care of you, unless you are literally collapsing on the floor or were brought in by paramedics... Of course, it is much better in some single-payer systems (UK seems to have very good healthcare system, and single-payer to boot, for example), so I'm not saying that American model is uniformly better (it isn't). The major problem with single-payer system is that prices set by the payer might not reflect the costs of the procedures undertaken. This is why, in Poland, once you are admitted to hospital, you are spending three days there (our single-payer pays dramatically more for three-day stunt at the hospital than for two-day or single-day), even if it is unnecessary. Geriatrics is also almost non-existent for similar reasons - it's making hospitals lose money on pretty much every patient. Large amount of medicine is also fully paid by the patient (I have yet to receive one state-sponsored prescription), including any birth-control stuff. With pricing being controlled at a single point, there are quite a few possible problems that may or may not surface.

The free public education is another topic that seems to be quite problematic. For starters: 'free public education' usually means that you do not pay tuition fees for attending school/collage/university (I will use term university from now on, since most of my argument will be relevant to this stage of education). This does not mean that you have state-sponsored dwellings in the city where the university is; this does not mean that you have state-sponsored books, computer, learning materials, transportation to and from university, food, etc. I've personally known a person who couldn't afford going to (free) university due to those cost. Ironically, that person was able to study on privately owned, paid university, because it was much more open to working students (with classes on weekends and in the evenings, for example), which allowed her to work and study, and thus pay both tuition and rent, as well as other assorted expenses. Many people are only able to go through university (free, public university) with help of... student's loans. Granted, we are probably still much lower than 35 000$ on average (even accounting for the fact that 35k$ in Poland would be worth way more than in USA), but that's not the end.

We are getting underqualified graduates in useless fields. And lots and lots of them. There are few reasons for that. First is the fact that government pays the same amount for a student with a given major, no matter what the university. I.e. MIT is being paid x for every CS major there, and University of Houston-Downtown is being paid x too. But MIT is probably spending way more money to teach their CS majors (more laboratories, better computers, better teachers etc.) than University of Houston-Downtown. In extreme cases, this might mean that MIT is losing money on each student, while UHD is gaining it, thus leading to a problem where MIT has limited amount of students and compensates with grant money (which it gets, because it's a good university), while UHD has little-to-none research going on, but twenty times as many students. And we have 20 times as many poor UHD graduates than we have good MIT graduates. Another reason is that the amount x is set separately for each major, but (similar to healthcare problem) this amount might have nothing to do with actual costs. For example, Math major might need a handful of pencils and a stack of paper to get through five years of higher education, but Chemistry major would need reagents, access to laboratory etc.. If there is the same amount of money paid for both, university is better off with Math majors than Chemistry majors. Worse yet, in Poland it seems to be more Sociology, Political Sciences and Philosophy, as those are 'cheap' (no laboratories; a lot of teachers with no jobs, so low salaries; etc.), not Math. And since this is free, there is little reason for students to think about choosing some other major, leading to peculiar problem where there are - at the same time - a lot of people who couldn't find work and a lot of employers who can't find employees.

TL;DR - keep in mind that there are countries where those policies don't work, as well as those where they do work. ;)