Can Donald Trump be defeated in the Republican presidential primaries? The safe answer, if one were inclined to place a bet at this stage of the game, is a pretty clear "No." Trump is absolutely dominating the GOP field, and only one challenger has made any sort of splash in the public polling. In what will no doubt become a recurring theme, I read today the first article bemoaning how many challengers are now jumping in the race to try to de-throne Trump (titled, amusingly enough: "Return Of The Republican Clown Car"). Dire warnings that the 2024 race could mirror the 2016 race are already being muttered, as more and more Republican hopefuls either officially toss their hats in the ring or just contemplate a run from the sidelines. But to me, the crucial question which will determine if any one Republican can beat Trump or not won't depend on how many of them run, but how many of them are still left running when the voters start to head to the polls. Because if Trump is to be beat, the only way it will happen is if there are only a few candidates left standing by Super Tuesday. Ideally: Trump and one other. Any more added to the mix would reduce the chances of any one of them would have of actually besting Trump.

The problem, of course, with this facile reading of things is the political ego necessary to launch a presidential run in the first place. The qualities that convince a person that they are the best GOP choice to run are not conducive to selflessness and "doing what's best for the party" in the midst of a fierce campaign. Imagining several candidates altruistically deciding: "Well, I gave it a good shot but obviously Candidate X has a much better chance of beating Trump, so I will withdraw from the race and throw my support behind them" is somewhat of a stretch, you'll have to admit. But that's the only way Trump could actually be beat, most likely.

Of course, a lot can happen over the summer and fall. Debates will be held. Trump may face a growing list of court cases against him. The political media and the voters could turn their attention to a new "not Trump" darling at any point. Polling will ebb and flow. But even having said all of that, certain things seem almost baked into the cake at this point, and will likely not change all that much.

Donald Trump, back in 2016, only had to win over roughly a third of his party's voters to walk away with the nomination. It is instructive to take a look back at the polling from that contest. It wasn't until Trump essentially had the nomination sewn up that he ever cracked 40 percent with the Republican electorate. The highest Y-axis line on that chart is 45 percent -- even when he had secured the nomination, Trump never got even half of Republican voters solidly behind him.

Now take a look at this year's chart. Trump has not cracked 40 percent on this chart in a different way -- because he is polling so far above that mark. He hasn't fallen below 43 percent, to put it another way. He is currently comfortably above 50 percent. That is beyond impressive; it may well be insurmountable.

Trump seems to have a hardcore base of around 30-to-35 percent of Republicans. These might be called "only-Trump" Republicans. Trump could shoot someone on Fifth Avenue on live television, and they'd cheer him on and continue supporting him. His numbers may fall somewhat over the course of the campaign, but it seems a pretty safe bet that he's built a "floor" of around a third of the party's voters.

One-third can be beat, though. After all, it would mean that two-thirds of the GOP voters weren't behind Trump. This is where the question of how many candidates are in the race will be critical, because it will all depend on how that two-thirds might be split up. Remember, Trump won handily in 2016 with only one-third support.

In 2016, there were only two candidates who ever even came close to besting Trump. The first was Ben Carson (remember him?), who took off in the polling in the fall of 2015. Once Trump's numbers took off, Carson was the only candidate to beat Trump in the polling average for the entire race, although it was just for one day and by a razor-thin edge. If the candidates who were polling somewhere in the neighborhood of 10 percent during the fall of 2015 (Jeb Bush, Carly Fiorina, Marco Rubio, and Ted Cruz) had all dropped out and endorsed Carson, he might have had a chance. But then again, he might not have -- Carson was another wildly unknown political outsider/newcomer who managed to give the voters some entertainment value for a while, but who ultimately collapsed faster than he had risen.

When Carson did fade, there was still enough time before the primaries for someone else to have successfully challenged Trump. Ted Cruz and Marco Rubio were the only two candidates to emerge from the Carson collapse with an increase in their poll numbers, and things could have been different at that point if Bush and Chris Christie (who were the only two polling anywhere near 5 percent by then) had bowed out and thrown their weight behind one or the other. If Carson had done so too, either Cruz or Rubio (Cruz, most likely, from the way the polling worked out) could have gained enough support to directly challenge Trump's standing. It would also have helped, at this point, if the huge pileup of candidates polling in the low single digits (too many to list) had also gracefully exited the race.

What really would have helped would have been Marco Rubio deciding to end his campaign (when he was in third place) and throwing his support behind then-second-place Cruz. If most of Rubio's supporters had moved over to Cruz, he would have been within striking range of Trump's polling. If Rubio and Carson had endorsed Cruz early on while ending their bids, Cruz might have been an actual contender.

But as we all know, none of that happened. The only candidates who started dropping out of the race before the first primaries happened were those polling somewhere close to zero percent. It wasn't until primary season had really gotten underway that any of the bigger candidates decided to call it a day. And due to the Republican Party setting up their primary system to deliver a winner very early on (by awarding delegates on "winner takes all" rules or close to them), by the time the major candidates dropped out Trump already had an enormous delegate lead.

This entire scenario could very well play out again, of course. That's where the "clown car" worries come from. Politicians who run for president are not generally known for their altruism or selflessness. They are known instead for their outsized egos and conviction that they -- and only they -- are the answer the country is searching for.

There's also a kind of Catch-22 built into the equation as well. Candidates who are polling near zero are the ones most likely to realize that they're not going to catch fire any time soon and be willing to pull the plug on their campaigns. It's easier to do so when you quite obviously don't have a prayer of winning (and/or when your campaign runs out of money). But these candidates only garner an insignificant level of support, so them dropping out wouldn't really change anyone else's numbers all that much. The only thing that would change the race is if people that are polling above perhaps five percent decide to call it a day. But they're all clinging to the hopes that their numbers will take off soon -- perhaps after a really good debate performance? The conviction that "We're just around the corner from seeing our numbers take off!" only gets stronger in the candidates the higher they poll. But it is precisely these mid-level candidates who could make a difference in the overall race by bowing out.

Also, nothing is guaranteed about how the polling would shake out. Just because one candidate drops out, their supporters might not automatically move to the strongest not-Trump candidate left in the race. Some might drift towards Trump, especially if the candidate who dropped out was running as a "Trump-lite" candidate.

As of today, there are seven announced Republican candidates in the race (technically there are more, it all depends on where you draw the line between actual candidates and vanity candidates). Three others are set to announce next week (Doug Burgum, Chris Christie, and Mike Pence). Two more seem to be seriously considering a run (Chris Sununu and Glenn Youngkin). Others might decide "What the heck?" and jump in the race as well (too many to list).

Ultimately, though, it's not going to matter so much how many Republicans run. The chances of any of them beating Trump are going to hinge on when they all get out of the race, not how many of them there are. The path to defeating Trump seems mighty narrow and not very likely. What would have to happen is that all the vanity candidates (those polling lower than five percent) decide in January that they're just not going to be the nominee and drop out. If they don't make a splash by then, with multiple debate opportunities and all their on-the-ground campaigning, then they never will. The contest would have to narrow at that point to perhaps four or five candidates (including Trump). Then as the early primaries happen, the ones scoring the lowest would also have to get out of the race -- before Super Tuesday. If there were only three (at a maximum) major candidates left heading into Super Tuesday, then one of the not-Trump ones might actually have a chance. If Trump's numbers have slid and there is one or perhaps two Republicans who are running competitively (which I would define, at that point, as "polling over 20 percent"), then they might have a chance to stop the Trump juggernaut from racking up so many Super Tuesday wins that the nomination is all but his. If Trump leaves Super Tuesday without the aura of inevitability, then there would be a real chance he could be beat.

That scenario, you will note, has a lot of "ifs" built into it. A perfect storm of events would have to happen for it to even have a chance of succeeding. And the iffiest of all the ifs would be the willingness of most of the Republican candidates to fall on their swords after running a monthslong campaign where they woke up each and every day convinced that they would be the best choice for president. And they'd all have to do so very early in the process for it to have any hope of succeeding. Which makes it all very unlikely to happen.

Donald Trump can be beat. Nothing is certain in life or in politics. Trump could self-immolate in some spectacular fashion. One of the other Republicans could catch fire in the polls. Anything could happen.

But, as I said at the start, from this incredibly-early vantage point, it sure looks like the safe bet would be that all the Republicans stay in the race far too long, dividing all the not-Trump vote up among them, and that none of them ever gets strong enough to actually challenge Trump in any of the early-voting states. Just like 2016. Back then, Trump was largely an unknown. Now, he's the most known person in politics. Everyone knows what they think about him. And he's sitting comfortably above 50 percent in the GOP polls.

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant