OK, I'll take a crack at it (sorry in advance for the wall of text). I am both left-wing and all about personal responsibility. My overriding world view is that, economically, a society should be structured to provide an equal opportunity for everyone (to the extent possible), to reward people appropriately for hard work/talent, and to provide a safety net for those who can't make it; socially, I think society should guarantee the civil liberties of all of its members.
Social first, as it's "easier" (a/k/a simpler to explain in concept, not easy to implement): to me, this means focusing on protecting the rights of the minority. The majority always gets its way through the power of democracy. The role of the federal government must be to protect its citizens against the tyranny of the majority in any individual state -- a LBGTQ kid shouldn't forfeit constitutional rights by moving to a red state, and a conservative Christian shouldn't forfeit rights by moving to NYC. Etc. This is where I conflict significantly with "states' rights" advocates -- to me, individual civil liberties trump states' rights.
Economically: to me, the question is how do you best create a system that allows each individual an as-fair-as-possible chance to succeed? Neither extreme works; you can take all the money from all the people and redistribute it, but then there is no incentive to work hard and learn and do better to get ahead; you can give people the absolute freedom to do whatever they want economically, but then you end up with Robber Barons and an oligarchy that just cements power within itself and doesn't give the vast majority of the populace a fair shake. So given the system we have, and that it will never be either perfectly equal or perfectly free, where do you draw the balance? For me, specific areas of opportunity include:
- Universal basic health care. The number of bankruptcies in this country attributable to giant health-care bills is ridiculous. But the opaque-ness of the process is perhaps even more difficult -- I am highly intelligent and highly trained, and I still don't have the ability to, say, ensure that everyone I deal with at a hospital is in my plan, or compare costs on an apples-to-apples basis. The complexity of our system is an additional tax on people with lower cognitive abilities.
- Education. Many states used to invest heavily in education as a path to economic growth; my FIL, for ex., went to school for free at CCNY. These budgets have been cut significantly over the past 20 years as state budgets became tighter, with more of the costs shifted to the students as a matter of state law. This also creates a perverse incentive for the schools to accept out-of-state and international students, who generally pay full price (and a much higher price to start). I am in favor of solidifying the CC-to-state-school link, with lower prices/free CC tuition, 100% clear transferability of credits (a big issue in many states), and improved state funding of the state education system.
- Taxes. First, they are probably going to be higher given my preferred social investments, and I'm ok with that. But I think there are efficiencies to be gained and it might not be entirely additive -- based on a recent post elsewhere, it looks like I am currently paying about the same amount as I would in Canada at our current income level, and yet I still get to pay for health care on top of that. Second, I think taxes are appropriately allocated on a progressive basis, meaning people like me should carry more of the burden. I am annoyed at various aspects of the tax code, which strikes me as clearly slanted to prefer companies and rich people over normal working stiffs. E.g., employment income is taxed at higher rates than investment income; businesses can deduct many costs that I can't as a person. And the complexity goes back to the same issue above: it is so difficult to work through that identifying and taking advantage of those tax breaks is almost impossible for those with fewer resources.
- Regulation of business. I am in favor of reasonable regulation to (i) provide a level playing field/minimum standard of conduct, and (ii) protect the individual liberties mentioned above. My huge problem is the way this is done -- the way Congress works is it keeps adding more programs and more layers to fix problems, and it never re-evaluates the old stuff to see whether it is still useful. I do environmental law, and the amount of money people spend just on trying to ensure compliance with the gazillion different requirements is pretty ridiculous -- not the emissions controls, mind you, just the personnel and the systems and the paperwork. Same with tax law -- why do we need to have so many different tax-protected ways to save for retirement (and why do corporate execs get different rules than everyone else?)? What's wrong with giving everyone a single bucket to fill as they choose? The amount of money we lawyers make just helping people navigate the current system is a sort of ridiculous tax on the economy.
- Social Security: I think it should be shored up. We need a basic safety net for people who are disabled, who don't make sufficient money to save much for retirement, etc. I also think AFDC is important, because no child should ever go hungry just because he chose his parents poorly.
All of these issues are far more Democrat than Republican issues. So I routinely vote Democrat. I vote for every school improvement bond, even though I know it will raise my taxes. I voted for Hillary, knowing that the end result would be that she would raise my taxes, because someone has to pay for this stuff, and I make more than most and can afford it. I'm probably going to personally make out like a bandit under Trump, but that doesn't provide any appeal at all, because it means society is moving away from the values that I hold dear -- if anything, Trump has induced a "bunker" mentality, a much more selfish sense that, well, I really need to look out for myself now, so let's sock away everything I can so I have more choices if the shit hits the fan (with "choices" being anything from being prepared to retire if the economy crashes, to moving to another country, to quitting to work for the ACLU. Note that I don't *actually* think horrible things are going to happen, but my brain naturally tends to look for the worst possible outcome so I can be prepared if it actually happens.).
To me, like an earlier poster said, it's about efficency: the way to "make America great again" is to take the maximum possible advantage of the talents of the maximum number of people possible. So investments in education, nondiscrimination laws, and a basic safety net for the inevitable individual failures seem like the best way to unlock that talent and ability. I was one of those kids who could have slipped through the cracks -- we were on food stamps for a while, and without them, I don't know if my mom would have been able to get her degree and have the stable employment that brought us to the MC. Both my mom and I have more than paid back the value of that temporary investment in the amount of taxes we have paid in our working lives. I want other kids like me to have the same opportunity, and I don't mind paying taxes to support them.
But I also don't think that is in any way inherently inconsistent with Mustachianism. I think our health care system is broken and the ACA was a good step but in itself insufficient; ergo, the subsidies are an imperfect way of addressing the holes in our current system, so I don't have a problem with people making the best of the system we are stuck with. I don't particularly think it's fair that our retirement system is so complex and that many people don't have good options, but that doesn't mean I should personally boycott my 401(k) -- that's cutting off my nose to spite my face. If I choose to retire before 65 or 70, that's my own personal choice to give up a future higher standard of living in return for more freedom today. Etc.
Tl;dr: Politics are about what I think our system should be. Mustachianism is about best navigating the system that we are currently stuck with.