Many people erroneously assume that polling is the exclusive determiner of who should be considered the frontrunner in a race. As we discussed last week, at this point in the game, polls are definitely an important data point, but they are by no means the only data or even the most meaningful data this early in the race. Remember: the Iowa caucuses occur almost a full month later this year than they did in 2012, and we are still a long way from the first ballots being cast.

In spite of what the polls at the moment say, which is that Trump and Carson are way out in front of Rubio, virtually everyone on the GOP side with political experience who does not have an axe to grind or ratings to boost will tell you, off the record, that they expect Rubio to win. At the CNBC debate I ran into people who actually worked for two of the other Presidential campaigns who confessed to me that they gave Rubio better than 50% odds to win at this point.

A good indication of this is the fact that pretty much all the other candidates right now - regardless of where they are in the polls or who else they might have an ideological interest in attacking - have their fire trained on Rubio. Donald Trump is basically in nonstop assault mode against all the other Republicans in the field (though not, curiously, against Hillary Clinton), but he clearly has remained focused in a special way on Rubio in spite of the fact that Carson has presented the first actual threat to his lead this year (although comparing Carson to a child molester was a nice touch).

Likewise, Jeb Bush's SuperPAC still has its sizeable war chest trained on Rubio even though the attacks he has leveled thus far have decisively backfired. None of this, though, really is new.

What's new is that both Sen. Ted Cruz (R-TX) and Sen. Rand Paul (R-KY) have also joined the fray over the last several days. Sen. Rand Paul (R-KY)'s campaign has basically been just waiting for an autopsy and for someone to claim the body for months now, so in his case it's more or less just another interesting data point about the extent to which people fully expect Rubio to be the candidate to beat next year.

The Cruz attacks, on the other hand, indicate something else entirely. Remember that throughout this entire campaign season, Cruz has steadfastly refused to attack Donald Trump, even as Trump's lead in the polls grew and grew, and even as Trump developed a monopoly on voters that Cruz needs to succeed. In fact, rather than attack Trump, Cruz actually followed him around and campaigned with him.

The fact that Cruz is attacking Rubio directly is one of the few significant developments in a campaign that has, for all the sound and fury to the contrary, been relatively stable for the better part of two months. Cruz has quietly solidified his status as outsider-in-waiting while everyone else has been focusing on Trump, Carson, and Fiorina. As much as some (including myself) have doubted his campaign strategy vis-a-vis Trump in particular, there can be no doubt that he has given himself the best possible chance to actually win going forward, as he now sits virtually tied with Rubio for third as we approach the period where voters are likely to pay attention.

Cruz's attacks on Rubio indicate, among other things, that Rubio is the first candidate Cruz sees as a direct threat to his plans. For a guy who has run a relentless and confident tortoise's race in a field full of hares, this deviation is very significant indeed.

Like Cruz, Jeb, Trump, and Sen. Rand Paul (R-KY), the predictive markets also see Rubio as the prohibitive favorite to win, regardless of what the polls might say.

It's very easy for people to indicate to a pollster that they are going to vote for Trump, or Carson, or some other candidate; which is why polling is so volatile and polling that is conducted this far away from the first vote being cast should be viewed with great skepticism. On the other hand, whenever people are asked to put their actual money where their mouth is - either in terms of deciding the direction of a multi-million dollar campaign strategy or participating in the prediction markets, they are overwhelmingly putting it on Rubio.

Which is a pretty good indicator of who the actual front runner in this campaign is right now.