Basically there are around 30% Demos, 30% Repubs and the rest are swing voters. Generally speaking, a candidate can count on the 30% from their party. The election results then depend on what the independent/swing voters do. In Romney's case, he was such a lackluster, lame candidate that over FOUR MILLION of that 30% Repub base refused to vote and, in effect, they gave Obama his second term. If the Repubs had fronted a better candidate, those 4 million voters would have went to the voting booths and Obama would have been a one-term president.
That makes sense, although I'd have thought the 30% Republican base would have turned out to get Obama out of the White House.
As for Sanders, I've heard it said that his socialist utopia would be funded with a NINETY-FIVE PERCENT tax rate which, of course, is not sustainable. These details would destroy him in a general presidential campaign.
Honestly, I think 95% taxation is fearmongering. From what I can see Sanders is looking towards a European-style socialism, which would certainly see taxation rise but it would most likely affect things like sales taxes rather than ramming the highest rate of income tax quite so high. Back in the 70s when the UK had a hard-left Labour government that figured the way to raise money was, in the words of Denis Skinner, "tax the rich until the pips squeak" it didn't work out so well. And in this age where a company can cross borders with nothing more than a stroke of a pen punitive levels of taxation aren't a viable option however left-leaning a candidate may be.
As I'm sure you know a company can move its headquarters with little more than form-filling. The very wealthy can move abroad easily enough and can shelter their wealth within corporations. The middle classes, whose wealth is largely made up of things like their physical property and maybe a modest savings account, are a soft target because they can't move so easily. Purchases are a soft target for higher taxes because everybody buys stuff sooner or later, and if you put taxes on food products you're all but guaranteed that 99% of people will pay more in tax (of course there are always the totally self-sufficient types who only eat what they grow, but you'll never do much to reach them).
Regarding healthcare, as Trump has said, he would "get rid of the lines." By this, he means state borders. He would erase the current rules that prohibit customers from seeking health policies from companies outside the borders (the "lines") of their own state. When this rule is erased, customers would be able to seek policies from companies in ANY state. It would open things up for customers to seek policies from companies all across the nation. It would open up the good ol' American spirit of competition -- which would probably lower the coverage costs by a dramatic amount. The companies would also have to accept all pre-existing conditions, which is one of the few virtues of ObamaCare.
One of the weird things I find out what is called health insurance in the US is that it isn't really insurance. We wouldn't expect our car insurance to pay out if we need new tires or an oil change, and yet we expect health insurance to pay for routine checkups and day-to-day costs of healthcare. What I'd really like to see is a system where you can get a basic policy that covers the bankruptcy-level costs of major treatment but doesn't constantly fiddle about covering the cost of a routine checkup. What Obamacare seems to have done as far as I can see is cause premiums to double in three years and then hand out money in the form of tax credits to bring the premiums down again but only for some people. Back in 2013 I got a quote for $300/month for a policy that had a $5000 deductible; in 2016 a comparable policy costs a little over $600/month.
If insurance can be taken out of the market in basic stuff like going for an annual checkup and low-level prescriptions it makes the cost cheaper for everyone. I still remember the time I needed a prescription when visiting the US - the pharmacist told me it would be $75 and asked what insurance I had. When I told her I was paying cash she grimaced, went back to her terminal and then said it would be more like $35. So effectively the cost of dealing with the insurance company more than doubled the price of the prescription. If anything needs addressing that would be a good place to start.
If there are federal prohibitions on insurance companies offering their products across state lines it would make sense to eliminate them.
As for Hillary? She is now infamously known to have allowed our people in Benghazi to be sacrificed on behalf of her and Obama's careers. She then began using that lie about an equally infamous -- and unseen -- video as the reason for the attacks -- when she knew it was a pre-planned terrorist attack. Then she repeated those lies to the faces of the grieving family members as they stood by the coffins. Her and Bill are now regularly confronted over this by angry voters. Hillary, by the last count, also had over 2,000 top secret security files on her private server -- catching her him in yet another lie as she has continued to insist that she never had any sensitive material on her server. This is a career criminal and time may be catching up to her.
The trouble with this twofold - firstly as you mentioned above there are the 30% of voters who would vote for a turnip if it had the Democrat colors on it, so she is assured of a good chunk of the vote regardless. And with the whole Benghazi thing, all the news reports I've seen on it are so partisan it's not funny. When you've got the media split between baying for her blood and insisting that multiple hearings have cleared her, it looks like nothing more than a partisan debate where one side is mudslinging and the other side refuses to hear anything bad about their candidate.
It concerns me that so many serious questions seem to relentlessly surround Hillary. Even if I got a vote in the election I wouldn't vote for her but even trying to take an objective look at things it seems that she's barely out of the news before she's in the news again for another concern. Truth be told I'd have thought that the presence of a single document classified Top Secret or higher on her personal (presumably insecure) server should render her unfit for high office let alone the presidency. But again the chances are the Republican fanboys won't vote for her anyway and the Democrat fanboys will just regard it as yet another Republican smear and continue to support her.