There's a concept in racing (NASCAR, bicycles, whatever) called drafting. The idea is that two competitors can see mutual benefit if one drives/bikes/runs closely behind the other. The one in front deals with wind resistance as he moves forward; the one behind deals with the drag.

It's not a perfect analogy for what's happening between Donald Trump and Ted Cruz, but it's not terrible either. Trump has been pressing forward and saying things that most other candidates would shy away from (to put it gently). Cruz has slipped in behind him, nodding along. And that's how they stand in the polls now, one-two. As of the most recent Washington Post/ABC News poll, Trump is at 38 percent and Cruz is in second, with 15 percent.

But the news for Cruz is better than that. Here's how the candidates compare once you combine voters' first and second choices.

No candidate is voters' second choice more than Cruz, meaning that as other candidates drop out — if any ever do — he stands to gain.

What's more, Cruz is by far the second choice of Trump voters. From a theoretical pool of 100 Republican voters, according to our new survey, 38 would back Trump (hence 38 percent support). If you then break down those 38 voters by where they'd go if Trump were to suddenly vanish, you discover that 11 of them would head over to Cruz.

Here's that calculus for all of the candidates, rounded to the nearest half person. (There is no such thing as half a person, by the way. Just go with it.)

In most cases, the numbers are too small to be noteworthy. And that's meant in a literal sense: They're simply not statistically significant. But the cluster that would head from Trump to Cruz shows how the senator's efforts to run close to the Donald are paying off.

This seems like a good time to revert to an old analogy, one that fits nicely with the drafting metaphor that I've been abusing. Polls are snapshots of races in progress, showing where all of the cars are at a given moment, before they speed off and rearrange. If Trump were to drop out today, which seems unlikely, this is how his support would splinter. But things change quickly, particularly in the high-stakes world of presidential politics. After a few more laps, the picture will be different. Maybe Cruz will have made his move.

If he does, it's probably not because Trump has crashed. The guy has hit the wall 200 times and somehow keeps gaining speed.

Okay now I'm done with the analogy. Wave the checkered flag.