WASHINGTON -- Donald Trump comfortably defeated his Republican presidential rivals on Saturday in South Carolina's GOP primary.

Trump's resounding victory isn’t simply a boon to his prospects for winning the Republican presidential nomination, an outcome once thought impossible that is looking increasingly more plausible. It is also an embarrassing repudiation of conservative orthodoxy that has dominated Republican politics for decades. It suggests that the party's intellectual leaders, who organized the base around the National Review/Weekly Standard consensus -- small government, free trade, pro-Israel, deregulation, low taxes, social conservatism and an aggressive foreign policy -- have been generals of a phantom army.

And where Washington and New York-based GOP leaders pledge outreach to immigrants, moderate Muslims and other minorities, the reality TV star plays more overt racial politics than any national candidate since George Wallace. Trump's brand of nativist, nationalist isolationism marked the path to victory. Rival candidate Jeb Bush is a dead man.

The Washington Post via Getty Images Real estate mogul Donald Trump, with supporters in North Carolina, enjoys free media coverage and has spent relatively little money on his campaign.

Conventional wisdom said that Trump was going to have a difficult time in the Palmetto State. After all, the brash real estate mogul failed to sway evangelicals in Iowa, a key group that is similarly prevalent across South Carolina. The thinking further went that Trump would also face an uphill climb with many veterans in the state, who are drawn to a candidate ready to assume the sober responsibilities of commander-in-chief. More than anything, however, Trump was expected to hit a wall named George W. Bush. The former president remains overwhelmingly popular among the state’s Republican voters, but not even he could convince enough South Carolinians to support his forlorn brother.

In the weeks leading up to the primary, Trump incessantly mocked Jeb Bush for relying on the aid of his famous family -- first his mother, Barbara, and later his brother. He gleefully tweeted that Bush “desperately needed mommy to help him. Jeb --- mom can't help you with ISIS, the Chinese or with Putin.” Bush campaign officials spun the jabs as a personal affront against the former first lady in hopes of winning votes, but Trump kept rising in the polls anyway.

During last week’s presidential debate in Greenville, South Carolina, Trump unloaded on George W. Bush’s presidency in a tirade that earned him plaudits from anti-war groups like Code Pink. He insisted that the former president “lied” to America about the existence of weapons of mass destruction in Iraq in order to start a war there and claimed that he lost “hundreds” of friends during the Sept. 11 terror attacks.

"How did he keep us safe when the World Trade Center came down?" Trump asked, referring to the GOP refrain that “Bush kept us safe” in the aftermath of the attacks, a line that helped him win re-election in 2004. He further stirred the pot after the former president re-emerged on the campaign trail on behalf of his brother, posing the question, “is he fair game for questions about World Trade Center, Iraq War and eco[nomic] collapse? Careful!"

The New York businessman had even harsher words for Sen. Lindsey Graham (R-S.C.), a defense hawk who is considered a powerful politician on the South Carolina scene, after he endorsed Bush. To Trump, Graham is merely a "disgrace" and "one of the dumbest human beings I’ve ever seen."

"He knows nothing. That’s why we’ve been in there for 15 years," added Trump about Graham, in reference to the nation's involvement in the Middle East.

The attacks were especially jarring because they didn’t come from a Democrat or anti-war liberal still sore about George W. Bush’s presidency -- but from someone leading the race for the GOP nomination.

Beltway pundits confidently projected that Trump’s performance at the debate would cost him votes of South Carolina Republicans still loyal to the presidential family. But once again, his poll numbers held steady, offering up yet another stinging rebuke to the Bush legacy. In the end, Trump capitalized on a structural weakness of Jeb Bush’s campaign that no amount of money could fix -- his last name. It turns out far more Americans are divided on issues like the Iraq War and whether George W. Bush truly “kept us safe” than Republican leaders believed.

Trump violated another core Republican Party standard on the eve of the primary when he vowed to stay “neutral” in conflicts between Israel and Palestine, with hopes of negotiating a deal between the two sides during his presidency. “You understand a lot of people have gone down in flames trying to make that deal," he said in an interview on MSNBC this week. "So I don’t want to say whose fault it is -- I don’t think that helps.” That statement was at odds with the rest of the Republican presidential field, and the GOP more broadly, which offers largely knee-jerk pro-Israel rhetoric to appeal to evangelicals across the American South.

The businessman followed up on Thursday during a CNN town hall by suggesting that he would preserve a health insurance mandate -- such as the one that's part of the Affordable Care Act -- and then reversing himself on the matter a day later.

Added to his promises not to cut Social Security and Medicare benefits, and his populist rhetoric against trade and Wall Street, it's a wonder GOP elites and their wealthy donors haven't done more to stop Trump's rise -- especially now this caucus victory gives him the chance to run the table in coming primaries across the South on his way toward the nomination. In the end, Republican elites found that in South Carolina, they couldn't beat something with nothing.

Editor's Note: Donald Trump is a serial liar, rampant xenophobe, racist, misogynist, birther and bully who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.

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PHOTO GALLERY Donald Trump On The Campaign Trail