Donald Trump’s hostile takeover of the Republican Party constitutes one of the most astonishing and seismic events in modern American history.

Trump, a property billionaire and reality TV celebrity, was regarded as the one of the least likely candidates to secure his party’s nomination when he entered the race as an underdog last June.

Pundits did not take him seriously — deriding his crass, belligerent, bombastic, bullying and unpredictable personal style, criticizing his simplistic policy pronouncements and sexist innuendos, blasting his underwhelming grasp of domestic and foreign affairs and disparaging his abysmal lack of experience in politics. If nominated, he would be the first Republican presidential aspirant since Dwight Eisenhower never to have held elective office.

Yet these deficiencies have not worked to his disadvantage. Indeed, they may have contributed to his unexpected success.

Trump had no problem vanquishing his 16 rivals, knocking them out like dominoes.

He eviscerated Jeb Bush, the front-runner, the ex-governor of Florida, the younger brother of the two-term president, George W. Bush, and the son of the 41st president, George H. Bush. He trounced Marco Rubio, the U.S. senator from Florida. And he handily defeated his last two competitors, Ted Cruz and John Kasich, who dropped out in ignominious fashion after their incredibly poor showings in Indiana.

And so Trump, against all odds and my own assessment of his chances, has become the presumptive nominee.

But as he stands poised to challenge Hillary Clinton for the presidency of the United States, the Republic Party establishment is up in arms over his meteoric rise, raising the prospect that the deep divisions over his candidacy may shatter the party into pieces.

Leading Republicans, having expressed shock and horror that Trump has cajoled and pushed his way to the top, have denounced him as a demagogue and a disruptive force whose views are not in alignment with party principles. 

“His is not the temperament of a stable, thoughtful leader,” observed Mitt Romney, the Republican standard-bearer in 2012. Paul Ryan, the Speaker of Congress, remains non-committal. And the Bush clan is boycotting him altogether.

To no one’s surprise, Trump has been attacked by a host of prominent figures who served in the Bush administrations. They run the gamut from Eliot Cohen, a former senior aide to the secretary of state, to Dov Zakheim, a top-level official in the Pentagon.

In an open letter published recently, they denounced Trump’s world view, claiming “his vision of American influence and power in the world is wildly inconsistent and unmoored in principle,” swinging from “isolationism to military adventurism within the space of one sentence.”

They took him to task for his skepticism of international trade agreements, his appetite for waging trade wars, his embrace of the “expansive use of torture,” his “hateful anti-Muslim rhetoric,” his insistence that Mexico must pay for the construction of a security wall along the U.S. border, and his insistence that Japan should pay far more for the expense of maintaining an American garrison there.

Since then, Trump — who’s campaigning on “America First” and “Make America Great Again” platforms — has come under fire for suggesting that NATO is obsolete and for asserting that women who have abortions should be punished.

Among American Jews, he generally inspires a mixture of puzzlement, anxiety and dread.

Jews were perturbed by his insensitive request that supporters at a rally should raise their right hands in a salute suggestive of Nazi Germany or fascist Italy. And they were upset by his evasiveness before denouncing the professional racist/white supremacist/Jew baiter David Duke. On May 6, Trump most definitely disavowed Duke after one of his vintage antisemitic rants, saying that “antisemitism has no place in our society.”

Trump — whose daughter Ivanka is a convert to Judaism and is married to Jewish real estate tycoon Jared Kushner — also caused something of  a commotion when he said he would be “neutral” in peace talks between Israel and the Palestinians.

He has since labelled himself as a true and reliable friend of Israel, denounced Obama for having “snubbed” Israel, vowed to move the U.S. embassy from Tel Aviv to Jerusalem, encouraged the Israeli government to build yet more settlements in the West Bank and urged the Palestinian Authority to recognize Israel as a Jewish state.

And much to the delight of conservative-minded Jews and Israel’s current right-wing government, he has promised to “dismantle” the nuclear agreement signed by the six major powers and Iran.

These statements may please Jews in the politically conservative and religiously Orthodox camp, but the vast majority of Jewish Americans will vote for Clinton, if past elections are any guide. Historically, Jews have favored Democrats over Republicans by a very wide margin.

Trump, of course, is not reliant on Jewish voters. He appeals, in the main, to a base of blue-collar and middle class workers whose manufacturing jobs have been drained away or are threatened by the new global economy, who are disgusted by the specter of rising income inequality, who think that immigration reform is long overdue and who are fed up with the business-as-usual political system in Washington.

Although he comes from the moneyed class, the one-percenters who have not been touched by the vagaries of the economy, Trump is boldly challenging the status quo. Like Democrat Bernie Sanders, he’s an anti-establishment politician. It’s clearly one of the reasons why Trump arouses so much fear and trepidation within the ranks of the elites.

Widely seen as a populist and nativist, Trump reminds me of the character Howard Beale in the 1976 Hollywood movie Network. In a memorable line, Beale declares, “I’m mad as hell and I’m not going to take it anymore.”

Disaffected Americans perceive Trump as a latter-day Howard Beale, an independent, unencumbered, outspoken politician/entertainer who will cut through the cant, tell it as it is and shake up the system, for better or worse.

Believe me, believe me.