What first seemed like faux pas and jabs at political correctness by Donald Trump have turned out to be a series of deeply troubling revelations about his malignant character and his seemingly pathological dishonesty. Trump’s campaign is providing Republican Party officials with repeated tests of their character, tests that they are failing again and again, to the long-term detriment of their party and our country.

Consider Trump’s devotion to — in his words — “getting even.” As he promised during the Republican primary, “Anybody who hits me, we’re gonna hit them 10 times harder.” He’s given us many examples, including his declaration during a rhetorical feud with Sen. John McCain that McCain (and by implication other prisoners of war) was not a war hero because he had been captured. “I like people who weren’t captured,” Trump said.

This Trump trait was on full display during the Democratic convention. When retired four-star general John Allen criticized Trump over his support for torture and other violations of international law, Trump responded by calling Allen a “failed general.” Michael Bloomberg, who Trump had previously called a “fantastic” mayor, became a “disaster” who “couldn’t get elected dog catcher.”

Most notoriously, Trump attacked Khizr and Ghazala Khan, the Muslim parents of an American soldier who was killed in Iraq. Khizr Khan challenged Trump’s vow to block Muslims from entering the United States, speaking movingly about his son’s sacrifice and asking Trump if he had ever read the U.S. Constitution. Trump considered this criticism a “vicious” attack, and responded to the family’s loss with shameful religious bigotry and innuendo.

When his actions generated significant outrage, Trump did not acknowledge error or apologize. Instead, his allies are doubling down on Trump’s bigotry. Mike Huckabee, for example, has flatly denied the fact of Trump’s repeated vow to block Muslims from entering the United States. Trump confidant Roger Stone and campaign adviser Al Baldasaro both promoted a stunningly irresponsible post from fringe extremists alleging that Khan is a Muslim Brotherhood agent and suggesting that his son was an Islamist double agent who was killed before his murderous mission was accomplished. Baldasaro tweeted a link to the article, saying “Read the truth about your hero.” (He later tweeted that he was “not sure” about the extremists’ credibility.)

In the face of this ugliness, most Republican elected officials have remained weak kneed or shamefully silent. Some have put out statements supporting the Khan family but they didn’t have the courage to criticize Trump by name.

Even John McCain, who strongly criticized Trump, has not repudiated his endorsement for a candidate whose recklessness has become undeniable. This is the same John McCain who, in refusing to consider President Obama’s nomination of the unquestionably well qualified judge Merrick Garland to the Supreme Court, is holding the vacancy open to be filled by the reckless, irresponsible and unprincipled Donald Trump.

More than 60 years ago, a dangerous, bullying demagogue was deflated with a simple question, “Have you no sense of decency, sir, at long last? Have you left no sense of decency?”

An open letter to Donald Trump from a group of Gold Star families echoes those sentiments, calling Trump’s comments about the Khans “repugnant,” and saying, “This goes beyond politics. It is about a sense of decency. That kind decency you mock as ‘political correctness.’”

It is time for Republican Party leaders to recognize that Trump poisons everything he touches, including, and especially, them and their party. Trump shares Joseph McCarthy’s cruelty and reckless disregard for others and for the truth. So the question must be asked of Reince Priebus, Paul Ryan, Mitch McConnell and other Republican leaders who have refused to leave Trump’s side: Have you left no sense of decency?

And we as Americans should ask ourselves, is there decency enough left among people of good will to reject Trump and Trumpism, and begin to recover an honest discourse, grounded in facts and shared values, about the future of our country?