Nigel Farage, the pro-Brexit leader, aligned himself with Trump during last year's campaign, spoke at his rallies and was among the first to meet with him after his election. On Friday morning, however, he said he was "very surprised" by the Syria action.
"I think a lot of Trump voters will be waking up this morning and scratching their heads and saying, 'Where will it all end?'" he said. "As a firm Trump supporter, I say, yes, the pictures were horrible, but I'm surprised," Farage continued, arguing that in a region riven by Islamic extremism, "whatever Assad's sins, he is secular."
Farage's comments captured the wave of right-wing anger and frustration that followed the US strike -- and they pointed up an odd reversal.
Populists who applauded Trump for his disdain for US interventions overseas and his campaign declaration that the US "cannot be the policeman of the world" were aghast by the strike. In contrast, an international community that has often held Trump at arm's length stepped up to declare their rock-solid support for the new US president.
French President Francois Hollande and German Chancellor Angela Merkel -- with whom Trump has had particularly chilly relations -- said that Syrian President Bashar al "Assad is entirely responsible for the development of the situation." NATO Secretary General Jens Stoltenberg agreed and added that any use of chemical weapons "cannot go unanswered." The Syrian chemical attack on a rebel-held town killed more than 80 people and injured more than 500, according to a Syrian Civil Defense report on the attacks.
Canadian Prime Minister Justin Trudeau announced that his government "fully supports the United States' limited and focused action to degrade the Assad regime's ability to launch chemical weapons attacks against innocent civilians." And Japanese Prime Minister Shinzo Abe said his country supported the US resolve.
United Kingdom Defense Secretary Michael Fallon told the BBC that "we fully support what the Americans have done," adding that the strike was "limited and wholly appropriate."
This made for a stark contrast to Farage, who urged Britain not to get involved in any further strikes. "Previous interventions in the Middle East have made things worse rather than better," Farage said.
The current leader of Farage's Independence Party, Paul Nuttall, said the strike was "rash, trigger-happy, nonsensical and will achieve nothing. I hoped for better."
"The whole world rightly condemns the use of chemical weapons in Syria, but the US attack on the Assad regime does nothing to lower tensions, nor will it hasten peace in that country," Nuttall said. "Too often, rash responses to horrific situations are about the conscience of the attacker rather than a clear-headed response to an awful situation."
In France, National Front leader Marine Le Pen also appeared to distance herself from Trump, saying on Twitter that she "strongly condemned" the "horrible" strike on the Syrian airbase.
"Is it too much to ask that we wait for the results of an independent international investigation before carrying out a strike like this in Syria?" she told France 2 television on Friday.
Populist leaders within the US registered their disapproval as well. "I'm deeply concerned that these strikes could lead to the United States once again being dragged back into the quagmire of long-term military engagement in the Middle East," said Vermont's Independent Sen. Bernie Sanders. "If the last 15 years have shown anything, it's that such engagements are disastrous for American security, for the American economy and for the American people."
Kentucky Republican Sen. Rand Paul, a staunch advocate for keeping the US out of foreign entanglements, called on Trump to consult on Congress. "While we all condemn the atrocities in Syria, the United States was not attacked," Paul said. "The President needs congressional authorization for military action as required by the Constitution, and I call on him to come to Congress for a proper debate."
Some foreign policy experts also expressed dismay.
John Glaser, the libertarian Cato Institute's associate director of foreign policy studies, said that "Trump's decision to attack the Syrian regime has no legal authority and little chance of actually mitigating the suffering of Syrians caught in the civil war."
Glaser went on the say that "the key now is to see whether Trump will be able to resist the temptation to escalate and avoid the kind of mission creep that has sucked the United States into hopeless Middle East quagmires in the past."
Further to the right on the political spectrum, Trump's alt-right populist supporters in the US also condemned the missile attack. "I guess Trump wasn't 'Putin's puppet' after all, he was just another deep state/Neo-Con puppet. I'm officially OFF the Trump train," Infowars' Paul Joseph Watson said.
"It's been fun lads, but the fun is over," he said in a post on Twitter. "I will be focusing my efforts on Le Pen, who tried to warn Trump against this disaster."
Right-wing commentator Ann Coulter, who campaigned for Trump, wrote on Twitter: "Those who wanted us meddling in the Middle East voted for other candidates."
"Trump campaigned on not getting involved in Mideast," she wrote. "Said it always helps our enemies & creates more refugees. Then he saw a picture on TV."
And former Brietbart editor Milo Yiannopoulos, who recently resigned in disgrace over comments that appeared to defend pedophilia, wrote on Twitter, "There comes a day in every child's life when his Daddy bitterly disappoints him."