They have a really big selling job ahead. Donald Trump and the Republicans now have to convince the American people that he and they are worthy of taking the reins of power in the United States and that The Donald is not merely a vindictive, racist buffoon who is in way over his head.

The just-completed GOP convention provided us with no shortage of amateurish intrigue: Who can forget Melania Trump’s plagiarism and the cheesy attempts to pretend that it didn’t happen? Or how about Ted Cruz being booed off the stage for refusing to endorse Trump in his speech? But after all the stumbles, finally, it was Trump’s turn to step out and describe how, as an outsider, only he can rescue the nation from the mess made by the insiders: “I have joined the political arena so that the powerful can no longer beat up on people who can no longer defend themselves.”

Next up, it will be Hillary Clinton’s job not only to defend herself as the personification of that establishment, but to convince the voters that she’s at least a likable-enough, and more importantly honest-enough, person to vote for. It doesn’t really matter who their vice-presidential choices are at this stage of the game — both Trump and Clinton have steep climbs.

On the one hand, she must emphasize her long experience compared with Trump, who has none. But that’s treacherous. He has already attracted millions who simply want to tear down our structures of government, world affairs and even civility and tolerance. Americans are fed up, and Donald Trump has been able to crudely exploit that. So far, he’s managed to take over the Republican Party. It would be foolish to believe he can’t win the whole thing.

But neither candidate is really going to focus on his or her own record. Instead, as we have already seen, they and their many surrogates will be trying to destroy one another. The Hillaristas will waste no opportunity to rip apart Trump’s business practices, which are dicey to say the least. They will continue to relentlessly paint him as a narcissist and a fraud who is grossly unqualified and, well, just plain gross.

As strong as the evidence was at the convention that the GOP has been ripped apart by Donald Trump, there was unity among the Republicans when it came to Hillary. There were constant calls to “lock her up,” demands to brand her a criminal. Some of the delegates’ rants ranged to the deranged. One suggested she be put in front of a firing squad and shot. The Secret Service is investigating that one.

She was literally demonized by Ben Carson — you remember him. He claimed that she and her mentors had been influenced by “Lucifer.” That’s Ben for you. But they all detest Hillary Clinton, even those who oppose Trump.

The Democrats have their own devilish unity problems: the bitter feelings still harbored by the millions who marched on the left flank with Bernie Sanders. Even though he says he will do whatever it takes to defeat Trump, what will be first is convincing his true believers that half a glass full of Hillary is far better than Donald Trump, who would shatter the glass — in fact, shatter everything. Right now, many of them are sulking, insisting that they just won’t vote in the general election. In making the case for her, however enthusiastically, Sanders will be the star of her convention.

To some degree, we know what we’ll see and hear in the days and months leading to Election Day in November. But it’s the unpredictable that could really decide: terrorist attacks, international developments like the attempted coup in Turkey, economic disasters, new disclosures about Hillary’s e-mails or about Trump University. We can expected shocking surprises and efforts to manipulate Americans’ fears. And get past our disgust.

Bob Franken is a longtime broadcast journalist, including 20 years at CNN.