Yes, Marco Rubio has taken a hit in the polls among Republicans. And yes, it’s probably properly attributed to his leadership on immigration reform.

Ignore those polls!

It’s absolutely appropriate for reporters right now to cover the 2016 nomination contests; after all, the candidates are actively running and party actors are at least beginning to make up their minds, so of course it’s a topic that we should be hearing about.

But it’s important to know what to pay attention to, and what is mostly window dressing. And at this point, virtually all polling is window dressing.

Indeed: The whole point of the “invisible” primary is that it takes place mainly among a relatively small group of people. Not too small — activists matter, and there are thousands of those, and there are plenty of campaign and governing professionals, formal party officials and operatives, and even politicians. But voters are really not engaged at this point. Sure, voters who keep the TV on Fox (or, on the other side, MSNBC) will certainly pick up on which candidates are being portrayed positively by party actors. They’ll also pick up on which ones are being bashed, and they’ll ignore those who are being ignored. But there’s no reason at all to believe that those allegiances, as registered by willingness to answer survey questions, is in any way predictive of anything.

As for immigration and Rubio: it’s just far, far too early to know whether and how it will matter to voters in early 2016. That will be affected by whether the bill is enacted into law or dies; whether conservatives keep the topic on the front burner; the composition of the candidate field by the time we get to Iowa and New Hampshire and on from there; and all sorts of other factors we won’t know the answers to for some time.

Truth is, I’m not convinced that national polling on presidential nominations is ever particularly useful. State polling in the run-up to a particular primary or caucus is absolutely predictive. But national polling, all the way through the process, involves asking people who are missing the campaign (because it’s not happening in their state) for their opinion.

About the only useful thing about this kind of early polling is entirely circular. If party actors believe in it, then it might influence what they do, which may eventually affect what the nomination electorate will do. So there’s that. But as far as meaning anything real . . . no, I don’t think these early polls really tell us much.

There’s plenty of important stuff to report about 2016, and there has been for months. But not the polls.