Donald Trump, the apparent Republican presidential nominee, attended the annual Rolling Thunder rally in Washington.
The event, now a decades-old tradition, honours veterans and draws thousands of bikers. At this year's event, some 5000 bikers motored past the Pentagon to the Mall.
The tradition began in 1987 when Vietnam War vets angry over the continued absence of missing comrades organised a mass convergence on Washington. The motorcycle was a vehicle of protest.
"If we have 5000 vans and pickups and cars come down to DC, people are just going to say it's a traffic jam," one of the event's organisers told the Washington Post. "If we bring 5000 motorcycles, they are there for a reason."
Trump, whose support for veterans has become something of a political hot potato, declared his backing for the cause at the rally. "We're with you 100 per cent," he said.
Bikers in attendance seemed to see a kindred spirit in Trump, whose campaign has been marked by his tough-talking, brusque manner.
"He speaks what's on his mind and means what he says," a 43-year-old contractor from Tennessee told the New York Times. "And that's what a biker does. That's the way we are: We say what we think. If you like it, you like it. If you don't, go the other way."
This is hardly the first time bikers have mobilised in Trump's favour. In recent months, reporters have noted the presence of muscle-bound, leather-clad bikers at Trump rallies across the country.
Groups such as Bikers for Trump have sprung up as a kind of volunteer security force, bent on protecting the candidate and his supporters from leftist protesters. They are joined by other organisations, such as Lions of Trump, whose website quotes the fascist Italian dictator Benito Mussolini as inspiration.
The phenomenon of biker gangs mixing with ultranationalism, of course, is not simply an American one. In fact, perhaps the most successful convergence of bikers and power politics can be found thousands of kilometres away in Russia, a putative adversary.
President Vladimir Putin has for many years cultivated a muscular nationalism, beginning with his own bare-chested persona. Right-wing Russian nationalist biker gangs have flocked to Putin's banner. Most famously, a hard-core group known as the Night Wolves has comported itself as Putin's hog-riding vanguard.
The pro-Kremlin biker gang deployed members to Ukraine following the annexation of Crimea and conducted parades through cities occupied by pro-Russian separatists.
It has also embarked on profoundly antagonistic bike tours of Eastern European countries that resent such gestures of Russian patriotism. The group's long-haired leader, Alexander Zaldostanov, nicknamed "The Surgeon," is on a sanctions list and is prohibited from entering the European Union.
As the Eastern Europe scholar Timothy Snyder observes, a coterie of Russian neo-fascists has cheered Trump's political success, seeing in the Republican candidate's tirades against globalisation, immigration and ruling cosmopolitan elites a like-minded politician.
"The American elite is not even American," Alexander Dugin, a far-right ideologue dubbed Putin's Rasputin, wrote in a recent blogpost. "Thus, there is Donald Trump, who is tough, rough, says what he thinks, rude, emotional and, apparently, candid."
Trump and Putin have made repeated statements indicating their mutual admiration, if not friendship. Judging from some of the foot soldiers in the ranks of their political movements, there's a great deal of common ground.