In his testimony before the House Intelligence Committee hearing Tuesday morning, former CIA director John Brennan bluntly told lawmakers that during the 2016 election, he reviewed intelligence that showed “contacts and interactions” between Russian actors and people associated with the Trump campaign. By the summer of 2016, Brennan said, he was “convinced” that Russia was engaged in an “aggressive” and “multifaceted” effort to interfere in our election — and as a result, he believed “there was a sufficient basis of information and intelligence that required further investigation” by the FBI.

With this testimony, Brennan just made it a whole lot harder — politically, at least — for the GOP to continue in its efforts to protect Trump, even as scrutiny of his campaign intensifies on the part of the FBI, and now, special counsel Robert Mueller. Yet if Tuesday’s hearing is any guide, congressional Republicans are still intent on shielding Trump by undermining the investigation in the mind of the public.

And so, again and again, Republican members of the committee, particularly South Carolina’s Trey Gowdy, tried to get Brennan to say that no evidence of Trump campaign collusion with Russian meddling in the election exists. But Brennan repeatedly refused to render a judgment on whether there was collusion. Instead, he only repeated his refrain that, because the CIA is not a law enforcement agency, he turned over its intelligence gathering about contacts between the Trump camp and Russians to the FBI, so that the FBI could conduct its investigation into whether there was collusion.

The result of this was that, by trying to get Brennan to say there was no collusion, Republicans made it overwhelmingly obvious that they are trying to undermine the investigation, or at least erode public confidence in it — as is Trump.

It’s crucial here to fully grasp the backdrop of Tuesday’s hearing. Just Monday, The Post broke yet another bombshell story: Trump had personally tried to get both the director of national intelligence, Daniel Coats, and the director of the National Security Agency, Michael S. Rogers, to publicly deny that there was any collusion between the Trump camp and the Russians. The Trump requests came after then-FBI Director James B. Comey testified before the House Intelligence Committee on March 20 and publicly confirmed, for the first time, that the bureau was investigating “the nature of any links between individuals associated with the Trump campaign and the Russian government and whether there was any coordination between the campaign and Russia’s efforts.”

It’s remarkable, then, that in the face of this deeply damning series of stories about the president’s conduct, House Republicans would take up his defense by using the opportunity to cross-examine Brennan — in hopes of undercutting the idea that an investigation is even needed. On Tuesday, less than a day after the story about Trump’s efforts to sway Coats and Rogers provoked instant comparisons to Watergate, House Intelligence Committee Republicans showed little interest in furthering public understanding — or even their own — of this unprecedented scandal.

Brennan, however, offered testimony that should only serve to deepen the curiosity about what really happened for anyone watching the hearing or its highlights. He repeatedly expressed his deep concerns about the intelligence showing numerous “contacts” between the Trump camp and Russian actors who were engaged in efforts to subvert our democracy.

Yet Republicans didn’t seem interested in learning anything from Brennan’s knowledge of how Russian active measures work. Instead they focused on trying to discredit any investigation. At one point, Gowdy directly demanded Brennan provide evidence of collusion; at another he asked Brennan if there was any evidence of collusion between Russian state actors and Trump himself. But all these lines of questioning failed to elicit any exoneration from Brennan. Any such information, Brennan told Gowdy, is “appropriately classified.” What’s more, Brennan said, “this committee has access to the documents we would have provided to the bureau.”

Each time Gowdy or another Republican pressed, Brennan had another opportunity to refer to “contacts” between Russian actors and the Trump campaign, thus amplifying the fact that such interactions had, in fact, taken place. The congressional Republicans’ efforts — like Trump’s — backfired, showing that it’s becoming ever harder for them to keep trying to make this investigation go away.