After the convention balloons have dropped, and before the all-important TV debates, there is a dangerous lull in US presidential elections. This is the period when John Kerry found himself swift-boated on his Vietnam War record in 2004, a duplicitous attack from fellow veterans that undercut his life story.

This is the same period four years later when Sarah Palin struggled in one TV interview to name a newspaper she read and insisted that she understood Russia because you could see it from Alaska. The post-convention doldrums can define candidates in ways their handlers never expected when they were writing their prime-time speeches and plotting the final weeks of the general election. Such is the fate of Donald Trump, who somehow managed to combine the worst week of the Kerry and Palin campaigns into just a single weekend.

Trump’s first failure was his decision to attack the parents of Captain Humayun Khan, who was killed by a suicide bomber in Baghdad 12 years ago. Khan’s father denounced Trump on stage at the Democratic convention last week, brandishing his copy of the constitution. He accused Trump of smearing American Muslims and said he had “sacrificed nothing and no one”.

There was a parade of speakers condemning Trump on stage in Philadelphia, and the Republican nominee could have taken his endless Twitter fights to any one of them. Why he chose to counterpunch against a bereaved family is hard to fathom. The Khans aren’t career politicians; they are ordinary immigrant citizens who suffered extraordinary loss for their adopted country.

Trump’s second failure was his normal tactics for public brawling: knee-jerk tweets and TV interviews. By this stage of the proceedings, the nominee may feel he has mastered the dark arts of both, having dispatched so many Republican rivals through the primary season.

But it’s one thing to punch in your own heavyweight class of public figures on a debate stage. It’s another thing entirely to punch down to a regular citizen. And it’s wholly unprecedented to punch the most respected regular citizens of all: the patriotic parents of a fallen war hero. Especially when those parents are willing to punch back.

Trump variously complained that the Khans had been unfair to him, that Khizr Khan had no right to speak, and that Ghazala Khan was forbidden from speaking. Ghazala Khan, meanwhile, explained in a Washington Post column (published in Gulf News’ The Views on Tuesday) and in a TV interview that she was still stricken with grief. “Donald Trump has asked why I did not speak at the Democratic convention. He said he would like to hear from me. Here is my answer to Donald Trump: because without saying a thing, all the world, all America, felt my pain. I am a Gold Star mother. Whoever saw me felt me in their heart.”

No meaningful response

It’s safe to say that Donald Trump will never understand the power of silence. He may also never understand the power of preparation for a TV interview. When George Stephanopoulos asked him in an interview on ABC over the weekend about the Khans’ criticism, Trump had no meaningful response.

“I think I have made a lot of sacrifices,” he blustered. “I’ve worked very, very hard. I’ve created thousands and thousands of jobs, tens of thousands of jobs, built great structures. I’ve done — I’ve had tremendous success.”

Stephanopoulos appeared incredulous. “Those are sacrifices?” he asked. “Oh sure,” said Trump. “I think they’re sacrifices.”

For a candidate whose entire campaign is built on the notion of restoring American pride and patriotism, this represents his third colossal blunder. You can argue about the need to crush Daesh (the self-proclaimed Islamic State of Iraq and the Levant), or about Obama’s leadership. But you can’t argue that a real-estate developer has sacrificed for the sake of the country by employing people.

Not like a Gold Star family has sacrificed. Unless you are willing to ignore reality entirely, which leads us to Trump’s fourth failure of the weekend, in the same ABC interview.

When pressed on Russian President Vladimir Putin’s aggression against Ukraine, Trump declared: “He’s not going into Ukraine, OK? Just so you understand. He’s not going to go into Ukraine, all right? You can mark it down, and you can put it down, you can take it anywhere you want.”

“Well, he’s already there, isn’t he?” asked Stephanopoulos. “OK, well, he’s there in a certain way,” explained Trump, “but I’m not there yet.”

Trump’s collapse in the face of a five-word question is more than a little problematic, given his projection of supreme self-confidence and honest straight talk. If Trump really is a Manchurian candidate — a Russian sleeper agent pretending to run for president — he is a remarkably incompetent one. One of the many challenges of Trump’s pro-Russian positions is that they undermine entirely his patriotic promise. According to recent polling by PPP, just 7 per cent of Americans view Putin favourably, and 35 per cent of voters say they are less likely to vote for a candidate seen as being friendly toward Russia.

For the older generation that is the bedrock of Trump’s support — a generation that was defined by the Cold War — a friendly attitude to Russia is the polar opposite of Reagan’s promise to make America great again. As Trump’s weekend meltdown took place, the traditional defenders of a GOP nominee are nowhere to be found. The Republican House speaker and Senate leader both issued statements heaping praise on the Khans.

After three days of GOP bleeding, John McCain attempted to rescue his party from the Trump meltdown. “While our party has bestowed upon him the nomination,” he said in a statement, “it is not accompanied by unfettered licence to defame those who are the best among us.”

And Fox News, which launched the swift-boat attack on John Kerry, is undergoing its own version of regime change, now that its creator and spiritual leader, Roger Ailes, has been ousted by a torrent of sexual harassment claims. Which leaves Donald Trump about as exposed as Sarah Palin when she prepared to walk on the debate stage eight years ago.

Midway through Palin’s debate rehearsals, the poor souls tasked with prepping her turned to one another in disbelief. “This will be a disaster of epic proportions,” said one. It already is for Donald Trump.

— Guardian News & Media Ltd

Richard Wolffe is a Guardian US columnist.