The writings on its walls offer testament to Portland’s wretched spring. “Tell everyone on this train I love them,” stands out in pink above a makeshift memorial of flowers and candles and myriad other messages written in chalk outside a light-rail station in the city’s northeast.

Several miles away in Chapman Park in the city centre two fresher messages adorn the brick of a public lavatory in spite of efforts to scrub them away. “F**k Cops No Exceptions” is one, written in thick black marker. The other reads: “Stab a Nazi, Twice”, beside a smiley face.

It was on a train passing though the light-rail station ten days ago that three men stood up and tried to stop another passenger from hurling racist insults at two black teenage women, one of whom was in a hijab. The raging passenger, Jeremy Christian, allegedly turned on them, killing two with a knife to their necks and injuring the third. He is now in custody charged with aggravated murder.

Such seemingly random brutality on a commuter train would have shocked any city. But as details about Mr Christian emerged, a deeper anxiety settled in. In April he had attended a rally for the ultra-conservative alt-right in Portland, standing out by wielding a baseball bat and throwing Nazi salutes. He had a Facebook page filled with white supremacist rants. At a first court appearance, he taunted the gallery. “You call it terrorism I call it patriotism,” he yelled.

More was to come. One of the leaders of the April march and a local alt-right celebrity, Joey Gibson, was preparing to hold another rally in a federal plaza downtown. In spite of efforts by Portland Mayor Ted Wheeler to have his permit rescinded, the event went ahead as planned this Sunday. It drew national headlines as well as thousands of seething counter-protestors, many of them crammed into Chapman Park which adjoins the plaza and where the toilets stand.

Violence in the end was mostly avoided. Only about 300 attended the Gibson event, mostly white men from outside the city. The police, deployed in overwhelming numbers in full-out riot garb, eventually charged Chapman Park with batons and flash grenades to disperse the counter-protestors - some anarchists and many identifying with ‘antifa’, or anti-fascist groups, clad in black coats and black masks - and arrested fourteen people.

Graffiti left behind by counter-protestors on a public toilet in Portland's Chapman Park (David Usborne)

Yet Portland, for all its progressive and liberal airs, its food trucks and craft beer halls, has suddenly found itself an unwilling crucible for a new and bitter war between the extremes of America’s left and right. And the seething tensions that have been released, notably since the election of Donald Trump as president, are far from resolved. More such confrontations are sure to come, here and in other American cities. (Mr Gibson has his next rally planned for Seattle.)

“It’s going to be a long hot summer, the first summer of Trump, especially now this dynamic has been established,” warned Randy Blazak, professor at the University of Oregon and chair of the Oregon Coalition Against Hate Crime. “Wherever the alt-right show up so will the counter-demonstrators with lots of media coverage. So it becomes this battle for the soul of the country.”

The short-term strategy of the alt-right brigade is slowly becoming clear: to trigger a greater degree of violence than they themselves display and play the role of martyr, put upon and misunderstood by the so-called mainstream media and their counter-protesting foes. They succeeded in the left-right clashes that erupted at Berkeley in April after the university canceled a speaking engagement by one of their own and it worked in Portland too. It was the antifa militants who ended up throwing bottles and bloodied tampons at the police, not them.

They also win by dressing up their white supremacist agenda as something else. They vehemently disowned Mr Christian, the alleged train killer, on Sunday and described themselves as warriors merely for free speech. In that regard, Mayor Wheeler had played directly into their hands. “Free speech is a nice tool. It’s a cloak for much deeper racism,” Mr Blazak argued. “These folks are often tied to white supremacist groups yet they won’t call themselves that.”

Indeed not. “I personally believe that no one here, that I have personally talked to, is personally a racist, I would hope not,” offered John Romano, who flew from Los Angeles to attend the rally, complete with a shiny breastplate adorned with a Christian cross made of little American flag stickers and ‘Soldier for Christ’ written on the reverse. “I wouldn’t stand for that.” In the same breath he admitted to his own feelings of personal rage. “It’s hard for me to be forgiving or nice. In fact I am filled with hate and when I leave I will pray about that,” he said. And he went on to address his assessment of Muslims. “Their religion represents a threat to America and any other nation they are in,” he noted, adding he is happy with accepting Christian refugees.

John Lovell, from nearby Wilsonville, also at the rally, said there was no line to be drawn from Mr Christian to him and others attending. “You are going have one idiot, one bad apple and that was what we saw with those two young ladies. It was one bad apple.”

The media remain a useful foil, meanwhile. “We understand now they are promoting a narrative, they are not doing real journalism in the way it should be done from an objective standpoint as they are promoting organisations like Antifa,” said Tom Efferson, 28, a local water plant worker who attended the event in a T-shirt reading CNN Is ISIS. “It’s funny to me that somehow we are painted as the extremists and they over there, they have masks on.”

The parallel quarrel with the media was played out in real time by Baked Alaska, who briefly addressed the rally. An internet agitator of the nationalist right, he was once denied entry to an event organised by his own brethren who balked at his record of anti-Semitic remarks. Live-streaming from Portland to his followers he asked them to decide, yes or no, after being approached by this journalist for an interview. Should he speak with The Independent, he asked them? “Fake news!” came the answers in an ether torrent. The interview didn’t happen.

Counter-protestors trying to get their message across to alt-right rally-goers across the street in Portland (David Usborne)

Though fealty to Mr Trump was evident inside the plaza grounds - some wore hardened versions of his Make America Great Again red caps, for safety - it seemed shaky and perhaps slipping. “Trump is not my deity,” offered Mr Efferson. “He was our beachhead to get our voice out there but now we can take over. The people have their own voice now.”

That the election of Mr Trump and his rhetoric helped reinvigorate the alt-right movement is not in question said Alex Ross, a lecturer at Portland State University, who has a new book called Against the Creep of Fascism. They “are really coming out of the woodwork” in the wake of Trump’s rise to power, he mused. The genie is out of the bottle and, “it won’t be easy to put it back in.”

“It should be seen as distant or distinct from Trump, but it is still a little bit his child, though one day the child is going to eclipse the father,” Mr Ross argued. He pointed to the “dog-whistles’ issued by Trump to white nationalists - the Muslim immigration ban he is still fighting for and his evocations of the 11 million undocumented in America - and what he called the co-mingling into his administration of people with ties to the supremacist underground. He would include in that Attorney General Jeff Sessions, who when in Congress gave some elements of it succour, including to the Federation for American Immigration Reform, FAIR, founded by John Tanton, a former eye doctor from Michigan, which some have labeled a hate group.

It shouldn’t be a surprise that Portland fell into the sights of the alt-right, Ross argues, precisely because provocation is their main game. Like Berkeley, it is in fact a perfect stage for their kind of activism because it is so clearly identified with the liberal left. A huge reaction. in the form of counter-protests to their presence there, was almost guaranteed. “They are inciting rage and violence in liberal cities,” by design, he posited, adding that going to a place like Kansas City which is already more to the right would be pointless.

Yet, Mr Blazak of the University of Oregon, also points out that Oregon as a whole in fact has a deep history of white supremacist activism, which offers today’s messaging from Joey Gibson and Baked Alaska a chance for unexpected resonance across the state. It was founded in 1859 as the only whites-only state in the country. The KKK was part of the political fabric of Oregon in the 1920s and in the 1980s it struggled with a powerful skinhead presence. Portland itself remains the whitest of all of America’s large cities. “This is just kind of the latest chapter in a very long story in which Portland is both a progressive place and a regressive place at the same time,” he said.