The “Why didn’t anybody see Donald Trump coming?” debate in political/media circles has given way to the “What’s responsible for Trump’s popularity?” analysis. Although there is an abundance of explanations, it increasingly feels like Trump represents the inevitable fruit of the great talk-radio oak that is Rush Limbaugh.

Throughout his presidential run, Trump has astounded the punditocracy with seemingly outlandish statements that once would have torpedoed electoral chances, or at the very least warranted apologies. That began with a remark in which the candidate pooh-poohed Sen. John McCain’s war service, questioning whether the former prisoner of war qualified as a true “hero,” and proceeded to include impolite utterances about plenty of others.

Observers have waited for the fallout, time and again. But the Republicans supporting Trump ate it up — in part because they have been fed a daily diet of sometimes over-the-top, always colorful vitriol for the past quarter-century.

Limbaugh, obviously, is hardly the sole purveyor of this approach, or the lone provocateur — on either side of the spectrum — capitalizing on the confluence of entertainment and politics. Still, most of those who have successfully followed in his footsteps have studied that playbook, and among the rhetorical bomb-throwers, he and author Ann Coulter probably come closest to the inflamed artery Trump has tapped — including their shared, unabashed glee in discussing the hundreds of millions of dollars that Limbaugh’s talent, “on loan from God,” has brought him.

Through the years, Limbaugh hasn’t been immune to controversy, and his show has been downgraded to lesser outlets in some major cities, including Boston and Los Angeles — notably after calling law student Sandra Fluke a “slut.” The radio titan was also thrown for a loss during a stint as an NFL commentator for ESPN, where his 2003 remarks about the media rooting for black quarterbacks prompted a rather hasty exit.

“Republicans supporting Trump have been fed a daily diet of sometimes over-the-top, always colorful vitriol for the past quarter-century.”
@blowryontv on Twitter

Nevertheless, Limbaugh’s willingness to offend hasn’t done anything to alienate his most ardent fans (or “Dittoheads,” as they’re known); rather, their bond seemingly has grown stronger thanks to that attribute throughout the duration of the  Obama presidency. And just as talk radio represents a relatively small media niche, the hefty contingent of GOP primary voters who show loyalty to Trump is, in the broader scheme of things, a subset of a subset, accounting for less than 10% of the population, as statistical guru Nate Silver has noted.

To be clear, Trump’s rise has less to do with politics than it does with providing a flourishing environment for the crop he brings to the table. As Brian Stelter, host of CNN’s “Reliable Sources,” recently suggested, talk radio has served as “the seed, or the fertilizer, for Donald Trump’s success.”

There are assorted reasons Trump’s message has resonated with certain voters — from his outsider status to his blunt talk to perceptions of strength and leadership advanced, in part, by hosting on “The Apprentice” — but the key point is the mogul’s ability to ignore from the get-go the niceties and conventions that normally surround political campaigns.

From that perspective, Limbaugh hardly created Trump, who gradually built this profile through innate media savvy, including his regular phone-in appearances on “Fox & Friends.” But the candidate does owe the host a debt for helping to cultivate the conditions for a campaign where outrageousness is considered as much an asset as a liability.

The powerful influence of talk radio and Fox News has come with warnings, such as commentator David Frum’s assertion following the 2012 presidential election that Republicans have been “fleeced and exploited and lied to by a conservative-entertainment complex.” Yet while Trump might have forged a path that’s rare in politics, seen through the prism of radio, he’s playing a very familiar tune.