(Bill O’Leary/The Washington Post)

On Tuesday afternoon, White House press secretary Sean Spicer brushed off questions about why it took so long for the White House to fire national security adviser Michael Flynn after learning, on Jan. 26, that he was vulnerable to Russian blackmail. Spicer blithely characterized the warning about Flynn as merely a “heads-up,” adding that he believed “the process worked.” Trump, noted Spicer, had merely delayed firing Flynn because he was reluctant to “smear a good man.”

The questions arose after Monday’s judiciary subcommittee on crime and terrorism hearing that featured former acting attorney general Sally Yates and former director of national intelligence James Clapper. The pair testified principally about what the Trump administration knew about Flynn’s ties with Russia. Yates’s testimony, in particular, confirmed that the White House kept Flynn on for 18 days after she warned the White House that Flynn was at risk of being blackmailed by the Russians, because he had lied about his conversations with Russian Ambassador to the U.S. Sergey Kislyak.

Spicer’s remarks Tuesday are the latest in a persistent effort by the White House to employ a disinformation campaign to undercut the various ongoing investigations into Russia’s meddling in our election — and potential Trump campaign collusion with it. If Republicans don’t stand up to the White House on this, they will be responsible for helping him undermine public trust in the ultimate outcome of the probes.

The stakes could not be higher, given the nature of the Russian threat to Western democracies.

In a normal presidency, the White House would have been relieved to receive an alert such as the one Yates delivered about Flynn. But this is not a normal presidency. This White House has basically declared Yates the villain and Flynn the hero. On Tuesday, Spicer characterized Yates, a 27-year DOJ veteran, as “not exactly a supporter of the president’s agenda.” He was suggesting, then, that the White House didn’t take her warning about Flynn very seriously because of her supposed political agenda.

Meanwhile, Trump, mostly via his preferred mode of communication, Twitter, has been actively attempting to undermine the various investigations into his conduct and that of his campaign associates. In advance of Monday’s hearing, he suggested, without basis, that Yates, a career prosecutor, was politically motivated and leaked classified material about Flynn to the press.

Whether prompted by Trump or not, during Monday’s hearing, subcommittee Republicans seemed oddly uninterested in the fact that the White House had retained a national security adviser for 18 days after being warned he may be vulnerable to Russian blackmail, and might have kept him longer had his deceptions about his Russian ties not been reported in The Washington Post. Multiple GOP senators instead queried witnesses about the leaks that helped bring all of this to light.

More worrying than this deflection effort, though, is Republican silence in the face of a Trump Twitter torrent after the hearing concluded. “Director Clapper reiterated what everybody, including the fake media already knows — there is ‘no evidence’ of collusion w/ Russia and Trump,” the president wrote.

Trump then tweeted that “Sally Yates made the fake media extremely unhappy today — she said nothing but old news!” And then he tweeted that “The Russia-Trump collusion story is a total hoax, when will this taxpayer funded charade end?” Finally: “Biggest story today between Clapper & Yates is on surveillance. Why doesn’t the media report on this? #FakeNews!”

The White House also dispatched anonymous administration officials to assure the media — and hence, the public — that there is no evidence of collusion. Breitbart ran a story on the hearing that claimed, “there still remains no evidence of collusion between his administration and Russian agents, despite mainstream media reports to the contrary.” Trump’s favorite television show, “Fox & Friends,” amplified his complaints Tuesday morning. “A total hoax,” read the chryon echoing the president’s tweet. “POTUS blasts Russian collusion accusations.”

Let’s be clear, in case this isn’t obvious: It’s hard to know what the evidence actually is until an investigation concludes. Because a number of investigations are ongoing, many of the findings are still classified and cannot be publicly disclosed without imperiling the probes, as both Clapper and Yates emphasized Monday.

What’s more, Trump’s tweeted claim that Clapper said there was no evidence of collusion is simply false. He did not say there was no evidence of collusion; he only said he was unaware of evidence of collusion. That does not mean such evidence does not exist. In fact, Clapper told the subcommittee Monday that he only learned of the FBI’s counterintelligence investigation into Russian meddling when FBI Director James B. Comey first told the House Intelligence Committee about it on March 20 — two months after Clapper left his post as director of national intelligence. So Clapper would not be in a position to know about such evidence of collusion if it did exist.

Similarly, Yates did not say there was no evidence of collusion. She said only that she would not answer questions about it “because answering would reveal classified information.” Her refusal to answer, rather than being proof that evidence of collusion does not exist, is instead evidence that she is scrupulously preventing the dissemination of classified information.

But this tactic of claiming “there’s no evidence of collusion, so why investigate further?” has become a staple of White House manipulations of reality since Comey revealed the existence of the investigation in March. “Investigating it and having proof of it are two different things,” Spicer said on March 20, the day of Comey’s revelation. “I think it’s fine to look into it, but at the end of the day, they’re going to come to the same conclusion that everybody else has had,” Spicer went on. “So you can continue to look for something, but continuing to look for something that doesn’t exist doesn’t matter.”

Someone needs to tell Trumpland that the entire point of these investigations is to determine whether there was collusion, not to conclude there is no evidence now, therefore case closed.

If Republicans continue to let Trump get away with this, they will be aiding in his efforts to undermine active investigations — and the public’s trust in them. Republicans must push back — clearly, loudly, forcefully — on the president’s attempts to interfere with these probes and his ham-handed spreading of disinformation about them, or they will be co-owners of his deceptions.