Sen. Ted Cruz (R-Tex.) released a TV ad before Wednesday’s Republican presidential debate that, for political junkies, evokes Ronald Reagan’s 1984 spot, “The Bear.” For everyone else, it’s not so clear what Cruz’s threatening imagery is supposed to communicate, making it an effective dog whistle — the technique by which candidates use relatively innocuous language to excite xenophobia, identity-based anger or otherwise unattractive passions.

“There’s a scorpion in the desert,” a narrator says, as the video depicts a venomous arachnid with pincers and stinger crawling across a rocky, rust-colored landscape. “For most of us, its venom is a clear and deadly threat.” Whose venom? Which desert? It is the Islamic State? Iran? Syrian asylum-seekers? Illegal immigrants from Latin America?

“But others refuse to even speak its name.” The ad seems to be talking about terrorism here but doesn’t actually say so. Reagan’s bear was an obvious reference to Russia; Cruz’s scorpion isn’t an obvious reference to anything. Its name could be “radical Islamic terrorism.” It could also be “anchor babies.”

“Since the scorpion seeks our destruction, isn’t it time we recognize the scorpion for what it is, before it strikes again?” But, really, “it” is terrorists in Syria and Iraq, here, right? Not the few thousand thoroughly screened Syrian refugees the Obama administration wants to accept? And definitely not Mexicans?

Maybe it’s not a literal desert, just like it’s not a literal scorpion. So maybe it’s literally anything?

At this point, a pair of human legs in ostrich-skin cowboy boots appears on screen, confronting the scorpion, which backs off slowly. A picture of Cruz flashes onto the screen next to the words, “Leadership you can trust to protect America.” End of ad.

The message is that you must be afraid of a threat that some people don’t want to identify, as long as that threat could plausibly be represented by a scorpion in the virtually limitless world of metaphor, and that Ted Cruz is going stand up to it, whatever it may be. Cruz, of course, doesn’t have to own any of the more objectionable interpretations viewers might have. After all, he’s just copying Reagan’s Cold War-era “Bear” ad. But he can benefit from the anti-illegal immigrant bile of, say, the Donald Trump supporters he’s been courting, nonetheless. Even if the ad is mostly taken to be about terrorism, which is what sophisticated observers are supposed to conclude, it could easily feed into the heartless panic of those who want to turn away desperate refugees escaping Syria’s horrifying civil war out of fear that a terrorist might slip through.

Clever, Senator. And revolting.