President Donald Trump finally has a primary challenger from the right: former congressman Joe Walsh, now a talk-radio host in Chicago.

That Trump, with his bad behavior and dismal approval numbers, has avoided a more serious challenger reflects the difficulty of unseating an incumbent, especially one so popular with the Republican base.

So does Walsh have a chance against Trump? No. Because Trump is a master of the same game that elevated figures like Walsh to political prominence over the past three decades. Throwing rhetorical bombs to the delight of the faithful, marginalized voices have gained mainstream success because of a talk-radio-inspired revolution.

But Walsh has now soured on some of that bomb-throwing, which is precisely his problem. Talk-radio politics has become the key to stardom for Republicans, and the guy who sounds like a talk-radio host will get a better reception from GOP primary voters than an actual host trying to atone for it.

Years before Trump successfully rode the talk-radio airwaves to the presidency, one of the very first Republican politicians to understand and harness the political potential of talk radio was rising to prominence: Congressman Bob Dornan. Dornan used his experience as a Hollywood actor and talk show host to shape a colorful political style that won him nearly two decades as a representative from California. In Congress in the late 1980s, he was a frequent guest on talk radio. So good was he on the air that when talk radio's biggest superstar, Rush Limbaugh, took a vacation in the early 1990s, he turned to Dornan as a guest host.

Dornan possessed an acerbic edge on and off the air. During one stint hosting Limbaugh's show, with arms gesturing and face reddening, he shouted at a hostile caller, "Liberals don't have any answers, they're bankrupting us!" And while he wasn't a good fit for the staid environment on Capitol Hill — once losing his speaking privileges on the House floor for the day by exclaiming that President Bill Clinton "gave aid and comfort to the enemy" — he was perfect for the airwaves. After he left Congress in 1997, Dornan hosted his own syndicated radio show.

Dornan's popularity with hosts was also the catalyst for the first organized Republican outreach effort to talk radio, pioneering tactics that elevated both the party and the medium before bringing them into increasing conflict. Dornan's press secretary, Paul Morrell, observed that the congressman was flooded with requests for radio interviews, mostly from conservative hosts. Morrell saw an opportunity: Far-right congressmen like Dornan and the members of the Republican Study Committee, the marginalized fringe of the Republican minority before 1995, weren't getting invitations to appear on major national shows like "Meet the Press." But there were dozens of local talk-radio hosts thrilled to get some of their time.

That realization led to the Talk Right Initiative. The staffers organizing the initiative compiled a list of hosts and regularly sent out one-page fact sheets and member speeches along with a list of congressmen willing to do radio interviews. This kind of initiative would become standard Republican operating procedure by the mid-1990s as the party's leadership moved from a generation that valued negotiation to one that valued confrontation and talk radio.

During the early years of the Clinton administration, when Republicans were a minority fighting against the entrenched Democratic majority in Congress and a Democratic president, they enjoyed a synergistic relationship with talk radio. But once Republicans captured control of Congress in 1994, party priorities sometimes clashed with talk-radio goals. As leaders of the majority, Republicans like Speaker Newt Gingrich had to govern, which at the time meant making compromises and nuanced arguments that made for terrible radio. As Bob Walker, R-Pa., one of Gingrich's closest allies recalled, there was nothing "very entertaining about nuance."

Over the next decade, talk-radio hosts generally supported the Republican Party, but they never lost affinity for those members who could ignite the airwaves and electrify the audience with fiery rhetoric and demands for the most extreme positions and tactics. After all, their blunt statements and demands made great radio, the top priority for hosts. By the late 2000s, this rhetoric also became increasingly enticing to Republican base voters — the people who listened to talk radio and showed up in primaries — who were embittered with President George W. Bush and mainstream conservatives in Congress who had done nothing about government spending and agreed to compromise on immigration reform.

This frustration gave hosts even more reason to spotlight combative Republicans. As it became clear their listeners wanted voices that attacked the Republican leadership, hosts had every incentive to feed their appetite. In the late 2000s, hosts had to be wary about being outflanked by new voices on the airwaves and new digital media like Breitbart and RedState. Doing so might damage their relationship with listeners, the bedrock of their success commercially.

The result was a new generation of Bob Dornans, conservatives like Rep. Louie Gohmert, R-Texas, (a Sean Hannity guest-host); Rep. Jim Jordan, R-Ohio; Sen. Ted Cruz, R-Texas; and Rep. Joe Walsh, who used talk radio to gain prominence in the Republican Party. These men were heroes on the airwaves, even while wielding little actual influence on Capitol Hill. Their efforts at toppling the leadership they criticized failed spectacularly: Gohmert snagged only three votes when he challenged John Boehner for the speaker's gavel.

But unlike in earlier eras, the GOP leadership could not contain these rebels thanks to their prominence on the airwaves. In 2015, 34 House Republicans voted against the party leadership on a rule on a key trade bill — a cardinal sin in the House. One of the mutineers was Rep. Mark Meadows, R-N.C., a subcommittee chairman. In retaliation, House Government Oversight Committee Chair Jason Chaffetz removed Meadows from this post.

Instead of accepting his punishment, however, Meadows went on the offensive, and found allies in conservative media. In an epic tirade, host Mark Levin labeled the top Republican House leaders "the three stooges." He dismissed Boehner as a "moron" and a "fool" and Chaffetz as Boehner's "lapdog." He denounced Meadows's punishment as a "Stalinist move" and called for the Republican leaders to face primary challenges.

Within days, the members of Chaffetz's committee revolted, and the chairman reversed course, restoring Meadows to his leadership position.

This embarrassing defeat for the House leadership showcased the deep divide between Republican leaders and conservative media in the mid-2010s. Politicians like Meadows might infuriate their colleagues and party chiefs, but in the world of talk radio and cable news, they were principled heroes fighting the establishment in both parties. Boehner had tried to take away their platform, imploring Fox News honcho Roger Ailes to stop putting them on television. But he ran headlong into the reality of the media business: such members were a great show.

It's not surprising given this set of incentives in Republican politics that the first conservative primary challenger to Trump is a talk-radio host who found radio a better home for his extreme rhetoric and conspiracy-mongering than Congress.

But it's also why anti-Trump conservatives shouldn't get their hopes too high about the Walsh insurgency. Because Trump is still every bit an insurgent rebel himself, wielding the type of language and tactics that landed politicians like Walsh in the spotlight. While Walsh, by contrast, is partly renouncing those tactics, apologizing for some of what he said including repeated assertions that Barack Obama was a Muslim and for the way that hosts like him helped "create" Trump.

But talk-radio tactics are still the key to stardom in Republican politics, and when forced to choose, Republican primary voters are likely going to favor the president wielding this style over the former talk-radio host who is apologizing for it.

Brian Rosenwald is a fellow at the University of Pennsylvania and author of "Talk Radio's America." He wrote this article for the Washington Post.