I suspect Christie, Bush, Kasich, and Fiorina fade. Ben Carson is already fading. Despite Carson's attacks on Ted Cruz over urging Carson supporters to stand with Cruz, the facts are that Ted Cruz's campaign relied on CNN reporting to tell Cruz's supporters that Ben Carson was getting off the campaign trail after Iowa. Carson's campaign has cut fifty staffers and is already announcing more cuts after New Hampshire. Carson will be out soon. He is using Ted Cruz as a way to stay on life support, but his campaign is over.
Trump, as long as he stays in, is more an opportunist who will say and do anything to get elected. Trump was recently endorsed by former Senator Scott Brown, who won a special election in Massachusetts, lost re-election, then moved to New Hampshire to try to get back to the Senate. Trump has been hopping party to party since the '90s trying to get himself into power. The endorsement was fitting. The endorsement, like Sarah Palin's albatross around Trump's neck, will not save him.
That leaves Cruz and Rubio as the last men standing. Both have substantial war chests and heavily funded super PACs to run ads and build ground game operations. Rubio continues to get endorsements from political leaders, but Cruz continues to pick up sizable support from people mad at political leaders.
If voters feel like the 2016 election is the last election to save the American experiment, Ted Cruz really is their only option. If voters feel like things are coming to an end in this country without drastic action, they really do not have a choice between Rubio and Cruz. They have only Cruz. Cruz is the disruptive candidate. A voter who feels like the end is near without drastic action has to take the gamble on Cruz, who still has a good chance to win.
Rubio, on the other hand, is the candidate for voters who think the best days are still ahead of us regardless of what happens in 2016. Democrats may fear Rubio as a candidate, but the base of the Democratic Party does not fear him like Ted Cruz. They think they could wait out Marco Rubio, even after eight years in power, and see few of their advances surrendered.
Washington's lobbyists think that Marco Rubio will not be a disruptive force to them. They know Washington will still be mostly the center of people's lives to a greater degree with Marco Rubio than with Ted Cruz. Ted Cruz will burn Washington to the ground and throw lobbyists on the street. Marco Rubio will strategically raze parts of Washington, putting fewer lobbyists in danger than Cruz. At least that is the thinking, and it is the thinking that is reflected in the attacks on both men.
For critics of Cruz, he cannot win. The reality is that Cruz can win, but if he wins those lobbyists and politicians attacking him will be out of a job. The Washington elite have every incentive to stop Cruz because he absolutely would be transformational, though his path to victory may be harder than Rubio's.
For critics of Rubio, he will not go far enough. The reality is that Rubio may have an easier time winning, but his critics do not believe he will go far enough and do as much to fix the problems in Washington.
Cruz and Rubio would both be conservative to varying degrees. What is at stake between the two is how easy their election would be and how transformational their presidency would be. Rubio backers are looking at the path to the White House. Cruz backers are willing to take a gamble on the slog of a general election campaign so they can see Washington rent asunder.