Sometimes, in politics, fate grants you a rival who stirs the deepest enmity of swing voters, sending them stampeding to the polls motivated mostly by the goal of defeating that other passion-rousing candidate.
And sometimes fate sticks you with Joe Biden.
One of Donald Trump's biggest challenges in this election is too few voters seem exercised about his rival. Survey after survey suggests that critical moderate swing-voters are generally OK with this year's Democratic nominee. Even Biden's own supporters profess to not being especially animated by him.
If those types of key voters wind up turning out for Biden in a way they didn't for Hillary Clinton in 2016, as polls suggest they might, that would likely end the Trump presidency.
That speaks to the power of negative partisanship — the notion that elections are often decided by whom voters dislike, as much as by whom they like.
Trump spent his prime-time speech to the Republican convention trying to tie his rival to something those moderate swing voters deeply, passionately dislike:
Radical, left-wing socialism.
WATCH | Part 1 of Trump's acceptance speech:
In other words, the president argued, the real political power in today's Democratic party is not held by an unobtrusive 77-year-old centrist, but by the party's fringes.
"Biden is a Trojan horse for socialism," Trump suggested.
"If Joe Biden doesn't have the strength to stand up to wild-eyed Marxists like Bernie Sanders and his fellow radicals … then how is he ever going to stand up for you?"
Rand Paul just got chased by a crowd back to his hotel, after leaving the White House from Trump's Republican Party Nomination <a href="https://twitter.com/hashtag/DC?src=hash&ref_src=twsrc%5Etfw">#DC</a> <a href="https://twitter.com/hashtag/DCProtests?src=hash&ref_src=twsrc%5Etfw">#DCProtests</a> <a href="https://t.co/h1kPcZG1jh">pic.twitter.com/h1kPcZG1jh</a>—@BGOnTheScene
He argued that the police-defunding, fossil-fuel-opposing flank of the Democratic party would easily overpower Biden, control the governing agenda, wreck the economy, and cause chaos in the streets.
As if to illustrate his message of looming mob-led disorder, a crowd in downtown Washington, D.C., swarmed attendees leaving the Trump speech.
Will it work for Trump?
Will Trump's approach persuade Americans to recoil from Biden — and to either vote for Trump; vote for a third party, as so many did in 2016; or simply to stay home?
In interviews conducted last weekend in a bellwether county in the key swing state of Michigan, some conservative-leaning voters echoed the president's concerns.
WATCH | Part 2 of Trump's acceptance speech:
Kel Giese, 20, made clear she's no Trump admirer. The resident of Michigan's Kent County, who leans Republican, said she has considered voting Democrat.
But ultimately she said she's frightened by what she sees as an increasingly radical Democratic party that, in her view, has not sufficiently denounced violent protests.
"I'm going to probably vote for Trump," she said.
"The vote for Trump is not in support of Trump. It's because the other side is scary ... the riots that have been happening recently are scary. The protests that turn into riots — and the left's reaction."
Yet she makes an entirely different prediction about the broader election result. She thinks most voters will pick Biden, and that Biden will win. Why? "He's a more agreeable candidate. I think people who are undecided are going to go for Biden."
Trump's accusations versus the public record
Indeed, Trump's sales pitch has its challenges.
Biden had a voting record smack dab in the middle of the centre-left when he was a senator, according to a formula used by political scientists to assess voting patterns.
In a group of 51 Democrats and Democratic-aligned senators, in Biden's final term in Congress, he had the 27th-most liberal voting record.
That was far behind the No. 1 progressive: Sanders.
Is Biden anti-police? That charge squares poorly with a contradictory message at the Republican convention. Several speakers argued Biden was previously too tough on crime — and sent too many African American people to jail with laws he endorsed.
Economy destroyer? In the last Democratic administration, in which Biden was vice-president, the economy kept growing after the 2009 recession and achieved rates of expansion in 2014 the Trump era hasn't ever matched. Unemployment steadily fell.
WATCH | Republican strategist Rick Wilson says Trump is trying to scare voters:
Overpowered by the left? The idea that Sanders and the so-called progressive squad now run the Democratic Party is at least somewhat underscored by the results of this year's presidential primaries, ultimately dominated by Biden.
It's true that Biden has adopted a platform significantly to the left of Barack Obama's. The platform was finalized in negotiations with pro-Sanders progressives including first-term congresswoman Alexandria Ocasio-Cortez.
Trump listed a few of those policies in his speech — while leaving out key details. He said Biden would raise taxes and destroy people's retirement savings. (Biden's proposed income-tax hikes would affect people earning over $400,000)
He said Biden would ban the deportation of undocumented migrants. (That doesn't come up in Biden's immigration platform. What the platform does commit to, and what Biden promised in a primary debate, was a halt for 100 days)
Canada: You've seen this play before
Any Canadian interested in the science of negative partisanship need look no further than our own last federal election.
The Trudeau Liberals embedded it into the core of their election strategy.
After the campaign was over, some senior strategists confided the reason the prime minister kept mentioning Doug Ford and Stephen Harper on the campaign trail — because his main rival, Andrew Scheer, elicited few passions from swing voters, and the Liberals invoked other conservative politicians who provoked stronger negative reactions.
Now Trump is deploying a similar tactic — only, in his case, his Doug Ford is Bernie Sanders.
While Trump's tactic was not new, his speech venue was.
Trump, forced by the pandemic to cancel convention plans in North Carolina and Florida, held a first-of-its-kind convention rally on the White House lawn.
According to his critics, he not only smashed norms — but also repeatedly violated the law that forbids partisan politicking with federal resources.
WATCH | Giuliani says Trump will make U.S. safe again:
Background documents prepared for Congress suggest there's some wiggle room for non-work areas of the White House.
But several officials in past administrations said any use of federal employees in the event, and in the subsequent fireworks display over the Washington Monument, would be a blatant violation of federal law.
Do you know what I see? <br><br>Literally thousands of Hatch Act violations— one for every federal official who helped with or participated in this revolting display. The greatest mass Hatch Act transgression in US history. <br><br>Even the fireworks are a violation. <a href="https://t.co/7xQbTMKoyo">pic.twitter.com/7xQbTMKoyo</a>—@NormEisen
Last week at their convention, Trump's Democratic rivals warned that Trump's behaviour was destroying democratic norms and whisking the U.S. toward autocracy.
So when Trump declared in his speech Thursday night that, "This is the most important election in the history of our country," he drew support from a rare place.
His rival, Biden, tweeted: "Donald Trump is right, this is the most important election in the history of our country."