Somewhere, we crossed a line - from our mothers' modesty to strutting braggadocio, from dutiful decorum to smashing all the china in the room, from respecting a base set of facts to a trumpeting of willful ignorance.
Yes, how did we get to a point where up to one-fourth of the party of Lincoln, Eisenhower and Reagan now aligns itself with Donald Trump? Those same political marshals would have us believe he's a "demagogue," a "jackass," a "cancer."
They say he's trashing the Republic brand. They say he's "stirring up the crazies," in the words of Sen. John McCain. But Trump is the brand, to a sizable degree. And the crazies have long flourished in the Republican media wing, where any amount of gaseous buffoonery goes unchallenged.
And now that the party can't control him, Trump threatens to destroy its chances if he doesn't get his way, running as an independent with unlimited wealth - a political suicide bomb.
Trump is a byproduct of all the toxic elements Republicans have thrown into their brew over the last decade or so - from birtherism to race-based hatred of immigrants, from nihilists who shut down government to elected officials who shout "You lie!" at their commander in chief.
It was fine when all this crossing-of-the-line was directed at President Barack Obama or other Democrats. But now that the ugliness is intramural, Trump has forced party leaders to decry something they have not only tolerated, but encouraged.
Consider Trump's swipe against McCain's military service, and by extension all veterans who have been involved in the fog of combat. Republicans were apoplectic at Trump's claim that McCain was no war hero.
"All of our veterans, particularly POWs, deserve our respect and admiration," said Jeb Bush. The Republican National Committee was quick to lay down a similar principle, saying, "There is no place in our country for comments that disparage those who have served honorably."
No place except a presidential campaign, that being the 2004 attempt to destroy the candidate John Kerry's record of honorable service in Vietnam. Where was Bush's "respect and admiration" when his brother was benefiting from a multimillion-dollar smear of a Navy veteran with a Silver Star, a Bronze Star and a Purple Heart?
The wise men predicted Trump's demise after he demeaned a former prisoner of war. But polls posted late last week showed Trump still in the lead. How can he get away with bashing combat veterans? Simple: The party he now wants to represent wrote the playbook on it.
The racism toward Mexicans that Trump has stirred up has been swooshing around the basement of the Republican Party for some time. Rep. Steve King of Iowa did Trump one better in 2013 when he said undocumented immigrants had "calves the size of cantaloupes because they're hauling 75 pounds of marijuana across the desert."
Did this make King a pariah? Not judging by the number of presidential candidates who showed up at his Iowa Freedom Summit in January, there to curry his favor. Among them was Rick Perry, the former Texas governor. This week Perry called Trumpism "a toxic mix of demagogy, mean-spiritedness and nonsense that will lead the Republican Party to perdition if followed."
Using the X-ray vision of his new glasses, Perry has correctly diagnosed the problem, and forecast the outcome. But that toxic mix has been just the tonic for his party for years, including Perry's suggestion that Texas might have to secede. Obama was barely into his first months in office when Rep. Joe Wilson of South Carolina shouted "You lie!" at him in a joint session of Congress. For hurling that insult, Wilson was widely praised in conservative media circles.
Trump also stoked the humiliating lie about Obama's citizenship. He began that crusade, he claimed, because so many Republicans still believe it and have encouraged him to keep it alive.
Now, the only way to trump Trump is to act like a fool in public. So Sen. Rand Paul, formerly seen raising good questions about national issues, fired up a chain saw and took it to the tax code a few days ago - a pathetic stunt. And there was Sen. Lindsey Graham, flummoxed by Trump's exposing him as sycophant to a plutocrat, destroying his cellphone in a blender. It only made us long for the real thing: Dan Aykroyd's Bass-O-Matic.
All of this overshadowed the entry into the race of Gov. John Kasich of Ohio, a sensible conservative who could beat Hillary Clinton. But he won't get any traction until Republicans destroy Donald Trump and the vulgar, nativist element in their party that they nurtured - until it became a monster.