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President Donald Trump was initially conspicuously quiet about the recent chemical attack against a former Russian spy and his daughter in the UK.

The White House on Monday condemned the attempted assassination as "reckless, indiscriminate, and irresponsible" but declined to back the UK's claim that the Russian government was behind the attack.

Trump finally issued a statement of solidarity with the UK on Tuesday morning, saying that if the UK believed Russia was behind the attack, "I would certainly take that finding as fact."

National-security experts were baffled and alarmed by Trump's delay in offering a public comment about a state-sponsored chemical attack on the soil of America's closest ally.

This month President Donald Trump made time to attack Oprah Winfrey, the "failing New York Times," "Sleepy Eyes Chuck Todd," "Pocahontas," and "fake as hell CNN."

But it took him a full day to stand in solidarity with the US's closest ally as it grapples with the fallout from a Russian chemical attack carried out on its soil.

The UK concluded on Monday that it was "highly likely" the Kremlin ordered the attempted assassination of 66-year-old Sergei Skripal and his 33-year-old daughter Yulia in Salisbury, England, earlier this month.

Skripal, a former Russian military intelligence officer, was a double-agent for the UK and has resided in the country since 2010, when he was traded as part of a "spy swap" between the UK and Russia. Investigators have said the Skripals were poisoned by the nerve agent novichok, which the Soviet Union developed in the 1970s and '80s.

British Prime Minister Theresa May gave Russia a deadline of late Tuesday to offer a "credible response" to the UK's findings. She said if it did not, she would conclude that the attack was "an unlawful use of force by the Russian State against the United Kingdom."

Asked about the attempted murder three times during Monday's briefing, White House press secretary Sarah Huckabee Sanders said it was "reckless, indiscriminate, and irresponsible." When reporters pressed her about whether she would name Russia as the perpetrator — as the UK did — Sanders declined to do so.

Former US Secretary of State Rex Tillerson later said the attack "clearly came from Russia" and vowed it "will trigger a response."

Following Tillerson's hardline comments about Russia, Trump announced in a tweet Tuesday that he was replacing Tillerson with CIA director Mike Pompeo.

While answering questions about Tillerson's ouster on Tuesday morning, Trump at last acknowledged Russia's likely role in the Skripal attack.

Trump told reporters that "as soon as we get the facts straight, if we agree with them, we will condemn Russia or whoever it may be." Referring to the UK's findings, he added, "It sounds to me like they believe it was Russia, and I would certainly take that finding as fact."

National-security experts were baffled and alarmed by Trump's delayed reaction to the chemical attack.

Hanging the UK 'out to dry'

Richard Kauzlarich, the former deputy assistant secretary of state in the Bureau of European Affairs, said the White House should have backed the British from the beginning.

"When you have the British come out as clearly and decisively as they did about who was responsible, the logic and gravity of the situation would require the president to say something in solidarity," he told Business Insider. "It should be almost automatic, especially with an ally this close to the US."

Edward Price, the former senior director of the National Security Council under President Barack Obama, echoed that view.

"For years, we heard from voices on the political right that America couldn't possibly confront its adversaries without first clearly naming them," he said. "And [on Monday], we heard the White House Press Secretary condemn the act but very deliberately skirt the actor, which, by all accounts, appears to be Moscow in this case."

He added that not only did the US effectively hang the UK "out to dry" by not naming Russia at first, but that it was also signaling to Russian President Vladimir Putin that "he is free to act with impunity, including by carrying out deadly acts in the UK."

The Skripals' attempted murder has prompted many comparisons to the 2006 death of former Russian spy and Putin critic Alexander Litvinenko.

Litvinenko, like Skripal, was a Russian defector who had been granted political asylum in the UK and later became a source for British intelligence. A decade after Litvinenko suddenly fell ill and died in November 2006, authorities found that officers working for Russia's security service poisoned him with the radioactive agent polonium-210, and that Putin was "probably" behind it.

"Russian leaders seem to go out of their way to get rid of anybody that seems to be in their way, someone who's betrayed them, someone who's interrupting the money flow, and they don't seem to care about borders," Joe Serio, an American author who spent nearly 10 years with the anti-organized crime unit of Moscow's police, told The Associated Press. "They just go wherever they have to go to get their guy."

Russian state television news anchor Kirill Kleimenov issued a chilling message to that effect in Russia days after the attack on the Skripals, implying that those who betray the Russian government should expect shorter lives.

"Alcoholism, drug addiction, stress, and depression are inevitable professional illnesses of a traitor — resulting in heart attacks and even suicide," Kleimenov said.

'What will it take?'

Moscow scoffed at the UK's latest accusations, linking it to the Skripals' attempted assassination, dismissing them as a "circus show."

The Russian embassy in London tweeted somewhat sarcastically on Saturday, "What a coincidence! Both Litvinenko and Skripal worked for MI6" (the foreign intelligence arm of the British government.)

Meanwhile, the White House's initial refusal to condemn Russia marks yet another incident in which the Trump administration "for whatever reason, is not prepared to put Russia on the spot," Kauzlarich said. "And Russia will draw the conclusion that anybody would: that if this president, for reasons no one can understand, will not criticize Russia on something this blatant, what will it take?"

"All of us who have been around the block find it bizarre that we would not be 100% behind the Brits on this," he added. "They've earned it. Russia hasn't."

Mark Simakovsky, a senior fellow and Russia expert at the Atlantic Council, echoed that claim and said the White House's delay in backing up the UK was likely why Tillerson felt the need to issue a stronger statement condemning Russia on Monday evening.

"The US and UK share intelligence, and details about who was behind this attack likely reached the White House pretty quickly," Simakovsky said. "Tillerson probably recognized that it was abnormal for the White House to go so long without issuing a statement supporting the UK's findings and felt like he had to step in to fill that gap."

NATO threw its support behind the UK following its assessment of the attempted murder, making it a point to highlight the Russian government's likely role in the "horrendous and completely unacceptable" chemical attack.

"If you've got an organization like NATO, of which the US is a member, essentially saying the same thing the British government and the US secretary of state did," Kauzlarich said, it makes the contrast between the White House's initial silence "even more vivid."

"In historical terms, this is far from normal," Price said. "But, for whatever reason, it's become the new normal under President Trump."