I would be shocked if John Kasich moved up, because he has demonized conservatism itself and tried to shame conservatives, hinting that he's a more compassionate practitioner. He exudes an impatience that voters don't recognize his superior goodness and competence.
Rand Paul is an accomplished retail politician and an admirable budget hawk. His fatal disability, though, is on foreign policy. Though probably not an isolationist, he has far too small an appetite for national defense spending, and if there's one thing most conservatives believe, it is that we must allocate sufficient resources to remain the strongest nation in the world and thus ensure our national security. To answer Paul's question: Defense spending is conservative because it is one of the responsibilities the Constitution assigns to the federal government.
Jeb Bush, as decent as he is, is not making his case. He needed to show why the country needs him, but he has chosen instead to tell us how Florida needed him years ago and why he is the guy who can unite America in bipartisan kumbaya. His problem is that Republican voters understand that the Democratic Party has no interest in working with us and that even if it did, our worldviews are so different that compromise might retard our national demise but not prevent it. The winning candidate will be one who denounces President Obama's destruction and offers a believable plan to reverse our national nightmare.
Donald Trump appears to be evolving as a candidate in exercising more restraint and avoiding personal skirmishes with other candidates. He will still bite back, as he did with Kasich, but not so reflexively or frequently. You'll note that though he piled on Carly Fiorina for interrupting, he only complained after someone else did. Trump's maturation will make it more difficult for his critics to dismiss him as cartoonish.
Trump's subtle evolution could be related to Ben Carson's rise and the media's shifting focus to bringing him down. The media vultures are out in full force circling over Carson, hoping they can make him into the next unelectable buffoon. They aren't even concealing their motive to influence events rather than merely report them. What they don't realize is that their assassination effort is the very type of behavior that is fueling Carson's (and Trump's) campaign. It also doesn't help them that Carson is not taking the bait. Carson's surgical unflappability is serving him well.
In the two most recent debates, Ted Cruz and Marco Rubio have nudged themselves up, both being extremely articulate and full of fight and energy. Though neither has moved into the Trump/Carson level, many observers believe that the race will eventually be between these two, once the inevitable implosion of Trump and Carson has occurred.
Note that I am not predicting this implosion, but I'm hearing it from people who cannot imagine that either of these two political neophytes will be the last man standing in the GOP contest. I admit I initially had my doubts that either could end up the nominee, but I don't see how anyone could dismiss that possibility now.
It's going to be very difficult for the media to take Trump and Carson out; they've been firing their heavy artillery and done little damage. That task is now left to the GOP competitors, and the campaign will reach a new level of intensity when that phase begins.
So far, Cruz and Rubio have been restrained in their attacks on other candidates, but at some point, they will probably have to take aim and distinguish themselves from the top two and from each other. Cruz, in my view, is the closest to Reagan conservatism. Rubio is very impressive, but he will have problems with the base unless he can satisfy it on immigration, and lately he seems to have lost even more ground on that issue.
So as the campaign progresses, we are likely to see one or both of them making a move on the front-runners, not necessarily because the top two will naturally slide but because Cruz and Rubio will be forced to distinguish themselves on policy and presidential ability from Trump and Carson. I believe that Cruz and Rubio will be very careful not to offend Trump or Carson or the supporters of the front-runners, but I don't think either will show similar restraint toward each other as the race unfolds. My guess is that Cruz will hit Rubio hardest on immigration and that Rubio will hit Cruz hardest on his alleged inability to work well with others.
I don't know how anyone could confidently predict the ultimate nominee, but I expect it to be one of these four, though Fiorina could still surprise us, and even if she doesn't make the top tier, she may well end up being someone's VP pick.
Republicans should be encouraged and invigorated by the depth and impressiveness of their field and by the abundant enthusiasm among these competitors and all other patriots for taking our nation back.