I'll make some general observations about how I evaluate presidential candidates, as well as some specific observations about Trump.
Does a candidate mean what he says? If a candidate says all the right things, but only says it to get elected, then you can discount whatever he says. It may check all the right boxes, but if he lacks credibility, what he says is worthless.
Many voters are rightly cynical of candidates because they have a habit of breaking campaign promises. However, we can draw reasonable distinctions:
a) Has the candidate taken consistent positions over the years? Or did he used to take more liberal positions, but suddenly moved to the right now that he's running for president? Does the "evolution" of his views coincide with the timing of his presidential bid?
b) When he's been in a position to act on his stated policies, has he done, or tried to do, what he said he'd do?
ii) Reading between the lines
If elected, I'm unsure how many campaign promises a candidate like Rubio or Walker will keep or try to keep. There's an element of uncertainty regarding their sincerity.
However, I'm quite sure that anyone Democrat candidate for president will be worse. There's no certain about where they stand on the major issues.
So we're comparing the uncertainty of how good or not so good the GOP candidate will be with the certainty that the Democrat will be very bad. On the one hand, there's better or worse. And the other hand, there's bad or worse.
That should be an easy choice to make. You're comparing certainties to uncertainties. If you can be sure the Democrat will be bad or worse, and you're unsure about the Republican, the choice ought to be clear.
iii) Ironically, even though nearly everything Hillary says is a lie, there's not much ambiguity about the direction in which she'd take the country. That's because you can reveal your position by trying to conceal your position. If you feel the need to hide what you really believe, and what you really intend to do, and if it's obvious that you are prevaricating, then that points to your real agenda.
iv) It isn't entirely clear to me why some conservatives are supporting Trump. Perhaps that's because it isn't very clear to them either. From what I can tell, they are supporting Trump for one or two reasons:
a) They think he'd make a better president than either a Republican candidate or the Democrat candidate. Apparently, they think that because of what he currently says.
If that's the reason, that's terribly gullible. There's no evidence that Trump cares about anyone besides himself. He's lived a life of wanton self-indulgence. His default political views mirror the social mores of the NYC cultural elite to which he belongs. He's a card-carrying member of the liberal establishment.
Currently, he's running agains the Establishment. To take that seriously is to be duped by his histrionics. Trump is a shameless opportunist. Don't confuse acting with conviction.
In fact, support for Trump is contradictory. On the one hand they say they support him because the GOP is so corrupt and compromised. On the other hand, Trump is running as a…Republican! But, then, doesn't that mean he's just as corrupt and compromised as the party whose nomination he seeks?
b) They don't care if he'd make a good president or bad president. They don't care if a Democrat wins.
For them, the real enemy is the GOP. That must be destroyed by any means necessary, whatever the cost.
One problem is what happens in the meantime. Suppose Hillary wins. That's the likely outcome.
She will get to nominate replacements on the Supreme Court for the next 4-8 years. She will get to nominate replacements on the Federal bench for the next 4-8.
The Obama administration already weaponized the Federal bureaucracies against conservatives and libertarians. No one has been prosecuted because Democrats control the DOJ. A Hillary presidency will solidify and escalate that totalitarian policy.
What will be the state of the nation after 12-16 years of Democrat presidential rule has consolidated the judiciary and Federal bureaucracies to trample dissent?
v) Suppose Trump either wins the GOP nomination or runs as a third-party candidate. There are two possible outcomes: (a) either Trump will win (b) or the Democrat will win. Both outcomes are worst-case scenarios.
Trump is a stealth Democrat. He will revert to his liberal establishment positions. And Hillary will be a vengeful, oppressive despot.
How is there a happy ending to that story?