One of the most watched of Brian Lamb’s iconic “Booknotes” programs on C-SPAN was with Robert Timberg and his 1995 book “The Nightingale’s Song.” Timberg, a Naval Academy graduate and a Marine officer wounded in Vietnam, asked why so many academy graduates played important roles in the Reagan era, specifically Oliver North, Jim Webb, John Poindexter, Bud McFarlane and John McCain.

The common thread, he discovered, was returning from Vietnam to a public scornful of their service and then having their pride reawakened by Ronald Reagan proclaiming that, mistakes aside, Vietnam was a noble venture. As stated on the book’s dustcover, “They shared a seemingly unassailable certainty. They believed in America.”

Supposedly, a nightingale raised in isolation can never sing until it hears another nightingale, and Reagan was the affirming nightingale who gave these men back their voice. It’s been 30 years since Reagan and 50 since Vietnam, but the same scornful voices on the left persist in their animus toward notions of American exceptionalism and Judeo-Christian values – and toward the “deplorables” and “clingers” who believe in such things. But after decades of desertion by moderates and derision by the elites, conservatives have found their voice in President Donald J. Trump.

And what an unlikely nightingale. A former pro-choice Democrat, Bill Clinton supporter, philanderer, liar, braggart, vain, egotistical, crude, rude, exaggerating, impulsive bull in a china shop of no political experience and seemingly no presidential temperament. Why do conservatives overlook such flaws? Because they see in him what Lincoln saw in Grant: He believes in America – and he fights.

And he wins. He fought in the Rust Belt while Hillary Clinton was measuring drapes for the White House – and won. He fought for tax cuts, deregulation, energy independence and Brett Kavanaugh – and won. He demanded that NATO members pay more for their defense – and won. And he’s taken on the global consensus on trade – and he is winning.

And so is America. Five million new jobs. Record low unemployment for blacks, Hispanics, and women. Stock market up 30 percent. Wages up 3 percent. Growth nearly double Barack Obama’s. And no apologies. Speaking Jan. 10 at the same Cairo venue where in 2009 Obama apologized for American Mideast policy, Secretary of State Mike Pompeo announced, “The age of self-inflicted American shame is over.” Trump’s July 2017 speech in Poland was the most powerful defense of Western civilization in a generation. He sings the ode to the joy of being an American and sees proud, patriotic nationalism as America’s bravado anthem against soulless globalism.

He sings the opera of opposition to anthem kneelers and political correctness and his supporters revel. He defends life and religious liberty and Christian conservatives embrace him. He reasserts American leadership in the world and rebuilds the military and national-defense conservatives salute him. He neuters the regulatory state and free-enterprise conservatives see the economy’s animal spirit unleashed.

And for all of that Trump is hated by the left with an intensity unsurpassed in American history because he threatens to derail the entire liberal project of the last 50 years. Three generations of Americans, marinated in the toxic worldview propounded by academia, popular culture and the media have come to see history as a one-way street moving inexorably to the left to the nirvana of a politically correct, border-free world running on valueless tolerance and windmills, in which evil American power has been shackled, like Gulliver by the Lilliputians. They don’t just disagree with Trump and his supporters, they think they’re evil and stupid. To understand the national political divide you need look no further.

In his Dec. 23 column, Greg Kesich spoke of the “stench of venality like bad breath” that emanates from Trump. Trump’s supporters, bound to him in being hated by the same people, see him instead as the indispensable man who pulled the country back from the tipping point … the freshening breeze that wafted the nightingale’s patriotic song and saved America from Hillary Clinton and descent into the progressive abyss.