Donald Trump violates political taboos so fast and so often it's very difficult to keep up, even for a political journalist. Just read through Photoshop whiz @darth's running thread of all the blatant lies, racism, conspiracy theories, and general madness surrounding Trump's campaign. It's dizzying.

Still, there's little doubt what the biggest recent controversy is: Trump's loathsome feud with Khizr and Ghazala Khan, the parents of Humayun Khan, a U.S. Army captain who was killed in Iraq in 2004. At the Democratic National Convention, Khizr, with his wife at his side, gave an extraordinary address asserting the rights of citizenship for American Muslims. In an instantly iconic moment, he asked if Trump had ever read the U.S. Constitution, and offered to loan Trump the copy in his pocket. Trump, nettled, attacked Khizr's wife, sneering that perhaps Ghazala had not spoken during the speech because she "wasn't allowed." Trump operative Roger Stone accused Khizr of being an agent of the Muslim Brotherhood. Really.

Ghazala herself retorted in an op-ed for the Washington Post that she had not spoken because she didn't think she'd be able to keep it together speaking about her fallen son. Khizr followed up with an interview saying Trump is a "black soul" who is unfit for the presidency. Various veterans' organizations piled on. Literally nothing in American politics is more universally valorized than soldiers who have died in combat. It's hard to imagine a more pointless and politically damaging fight for Trump to pick.

Trump, for all his facility with manipulating the media, is at bottom an impulsive and profoundly ignorant racist bully. But the reaction from establishment Republicans is equally damning. With a few exceptions, they have squirmed and rationalized past Trump's comments. It's a portrait of a party in utter moral and intellectual freefall.

Republican leaders distanced themselves from Trump's comments to varying degrees, of course. Trump's running mate Mike Pence praised Humayun Khan while reiterating support for a ban on Muslim immigration. Paul Ryan and Mitch McConnell denounced the comments while omitting where they had come from. John McCain and Kelly Ayotte — both in tricky re-election races — denounced Trump personally.

But none rescinded their endorsement. The reason is obvious: Many Republican voters are fine with bigotry. They support Trump's big wall to keep out Latinos. They support his Muslim ban. Ninety percent of Republicans want Trump to win. He is now the party's center of gravity.

It's when disaster strikes that one's character is tested to the utmost. And it turns out that this generation of Republican elites are, for the most part, cowards, bigots, fools, or some combination thereof.

This has been coming for a long time. Most recently, the Republican National Convention displayed a party convinced that ISIS can easily by defeated by invoking the right magic phrases. Most weirdly, party elites are fine with casually blowing apart the basic security guarantees that have undergirded American policy towards Europe for the past 70 years — and all apparently to get cash-strapped Baltic states to spend a measly few pennies on their armed forces.

The last Republican president was a sort of anti-Midas, a man who turned everything he touched into horse manure, who left office so despised his own party now barely mentions him, and whose later painting career carries a distinct whiff of psychological damage. Republican voters loved him right up to the end.

For decades now, Republican elites have stoked their base voters' worst instincts — their paranoia, conspiratorial thinking, racism, and anti-intellectualism. Now it's eating them alive.

It would be deeply satisfying to watch if there weren't a significant chance that Trump could actually win.