Two developments today force us to consider the place of the more unusual candidates in the presidential race, the ones who probably won’t end up being their party’s nominee but whose support tells us something meaningful about where the Democratic and Republican parties are and where they might be going. The first is that, according to the Huffington Post Pollster poll average, Donald Trump now sits atop the GOP field with an average of 13.6 percent support, nosing out Jeb Bush at 13.3. Yes, that difference is essentially meaningless, and yes, those are very small numbers to begin with. But it’s still alarming to see Trump’s name at the top of the list, to say the least.

The second development is the undeniable and growing support for Sen. Bernie Sanders (I-Vt.). Yesterday Sanders held a rally in Madison, Wis., that drew approximately 10,000 supporters, the biggest crowd any candidate has had for any event in the campaign so far. This follows on other rallies that have drawn thousands to hear Sanders, at a time when Republican candidates are speaking before audiences that often number in the dozens (not to mention that time Rick Santorum held an event that drew exactly one attendee).

It’s true that Madison is a liberal stronghold. But is there anyplace in the United States where a candidate like Sen. Ted Cruz (R-Tex.) or Louisiana Gov. Bobby Jindal, or even one of the first-tier GOP candidates like Wisconsin Gov. Scott Walker or Sen. Marco Rubio (R-Fla.), could get 10,000 people to come out to hear him talk?

And that support is being reflected in the polls, where Sanders is rising fast. A Quinnipiac poll of Iowa voters released today shows him trailing Hillary Clinton by only 19 points, at 52-33.

Some might protest that Sanders’s chances of beating Clinton remain slim. This may be true, but it’s also not really relevant. There’s something presumptuous about declaring that a particular candidate absolutely can’t win his party’s nomination. Who are we to say? Shouldn’t we avoid making prophecies that could become self-fulfilling? On the other hand, reality is what it is and it’s fine to acknowledge it, so long as we don’t let it lead us to ignore what’s actually happening.

So perhaps the best way to deal with that question is to say that right now, whether Bernie Sanders or Donald Trump is eventually going to be his party’s nominee doesn’t matter all that much. We’re seven months from the first ballots being cast. At this stage of the race, we should spend our time thinking about what all the candidates are proposing, who they are and what they represent.

It’s becoming obvious that Sanders is tapping into an important segment of the Democratic electorate, a group that wishes President Obama had proved more liberal than he did and been able to accomplish more. Because Sanders is attracting enough support to make Clinton at least a bit worried, it’s becoming more likely that she’ll move to incorporate those voters’ concerns in her proposals and her actions. That doesn’t mean she’ll be making radical changes in policy positions — don’t expect her to start advocating a single-payer health-care system, as Sanders does — but it does mean that the somewhat more liberal Clinton that we’ve seen in the past few months could become even more so, in small but meaningful ways.

As I’ve argued before, party nominees are always a reflection of their parties, and right now if we want to understand the Democratic Party, we have to understand both the Clinton supporters — who make up its majority — and the Sanders supporters, who make up a smaller but still substantial group.

And what about Trump? His story is a bit more complicated, because it’s hard to say that he represents some kind of coherent Republican constituency. I can’t say I understand who a Trump voter is or what he or she might be thinking. But if nothing else, Trump’s popularity, limited and probably temporary though it might be, offers a lesson in the political power of celebrity — even the most ridiculous celebrity. And it may be that the ugly anti-immigrant rhetoric that is leading one corporation after another to cut ties with Trump (the latest is Serta — did you know you could buy a Trump mattress?) is meeting an enthusiastic reception in some quarters.

Those are the kinds of questions we should be asking about these candidates, not whether they have a chance to win. What does their support tell us about the parties? Will the things they’re advocating find their way into the party platform and on to the next president’s agenda? Will it make their party more or less appealing to the general electorate?

A primary campaign is a contest that ends with one winner and a bunch of losers, but it’s also a rolling debate that helps define a party, both for itself and in the minds of voters. That debate, on both the Republican and Democratic sides, is getting more interesting. So it’s worth paying attention to, no matter who the winners will be.