There is no evidence President Trump’s campaign colluded or conspired with the Russian government during the 2016 election, but both his team and the Clinton campaign had “poor judgment and ill-considered actions,” the House intelligence committee concluded in a report Friday.

The report dings Mr. Trump’s family for making an attempt during the 2016 Trump Tower meeting with a Russian lawyer to try to get damaging information on Hillary Clinton, but says that was ultimately unsuccessful.

And the report blames the anti-Trump attitude among the GOP establishment in 2015 and 2016 with forcing the campaign to turn to less accomplished and more questionable foreign policy advisers George Papadopoulos and Carter Page — both of whom became subjects of FBI investigations over their relationship with Russian entities.

But there is no evidence of successful conspiracy or collusion, the panel concludes.

“When asked directly, none of the interviewed witnesses provided evidence of collusion, coordination, or conspiracy between the Trump campaign and the Russian government,” the report says.

Mr. Trump saw vindication.

“Just Out: House Intelligence Committee Report released. ‘No evidence’ that the Trump Campaign ‘colluded, coordinated or conspired with Russia.’ Clinton Campaign paid for Opposition Research obtained from Russia,” he wrote on Twitter. “Wow! A total Witch Hunt! MUST END NOW!”

That witch hunt comment would appear to be a reference to special counsel Robert Mueller’s ongoing investigation into the 2016 election and Russian activities.

In one striking part of the new report, the committee seems to tie former Director of National Intelligence James Clapper to anti-Trump media leaks surrounding the Steele Dossier. The report says when first asked, Mr. Clapper denied leaking. But he later acknowledged talking with CNN journalist Jake Tapper in January 2017 about the Steele Dossier, and “admitted that he might have spoken with other journalists about the same topic.”

Mr. Tapper would go on to publish an article that detailed the two-page summary of the dossier allegations then-FBI Director James B. Comey presented to Mr. Trump just days before he was inaugurated.

“Former Director of National Intelligence James Clapper, now a CNN national security analyst, provided inconsistent testimony to the Committee about his contacts with the media, including CNN,” the investigation concluded.

Asked about the allegation, CNN spokeswoman Lauren Pratapas said the network does not comment on “sourcing.”

The GOP report also concluded a widely-questioned change in the Republican Party Platform at the 2016 convention regarding Ukraine was actually anti-Russia, not pro-Russia, and said there’s no evidence then-campaign Chairman Paul Manafort was involved. Mr. Manafort has been indicted by the special counsel for his work with pro-Russian entities in Ukraine.

And the committee said there’s no evidence anyone in the Trump circle was involved in the theft of Democratic National Committee or Clinton campaign figures’ emails — though “Trump associates had numerous ill-advised contacts with Wikileaks.”

The heavily redacted 253-page report and a 98-page response by the committee’s Democrats come after a year of investigation into the allegations that dented Mr. Trump’s early months in office.

Overall the report confirms what’s been widely reported: Russian-backed operatives mounted a low-cost but highly effective interference campaign that included cyberattacks, online trolling, propaganda and stolen emails.

The FBI’s response “was largely inadequate,” Homeland Security’s efforts to get states to take the threats seriously were rebuffed and the Obama administration failed to tell the Trump campaign some of its figures posed counterintelligence concerns.

The committee’s Democrats, in their report, blamed the Republicans who run the committee for breaking a bipartisan commitment to the investigation, for cutting the probe short and for leaping to conclusions.

Ranking Democratic Rep. Adam Schiff said the GOP kept shifting its own conclusions. He said an earlier version disputed the intelligence community’s finding that Russia specifically tried to help Mr. Trump and hurt Mrs. Clinton. By the time of the report, the GOP “could no longer defend this claim and watered down its supposed findings,” Mr. Schiff said.

He said collusion was also there to be found if the GOP had looked at the data differently.

“In fact, we found evidence of collusion in the abundant secret meetings and communications between Trump campaign officials and associates such as Paul Manafort, Rick Gates, George Papadopoulos, Donald Trump Jr., Michael Flynn, Carter Page, and others, with emissaries and officials from, or linked to the Russian government,” Mr. Schiff said.

“The Trump campaign and administration’s efforts to deny, conceal and, when discovered, misrepresent what took place in these interactions with the Russians is powerful evidence of a consciousness of wrongdoing,” he said.

Democrats in their report also defended Mr. Clapper, saying he was authorized to talk to the media, and Republicans never proved he leaked secret information.

The Democrats included a section of transcript of Mr. Clapper’s interview with the committee where the former intelligence director says he couldn’t remember his conversations with Mr. Tapper but that the dossier was already in the hands of the media at that point.

“There was nothing inappropriate with his doing so, and it is hard to escape the conclusion that the majority simply wishes to impugn the integrity of a man with a lifetime of service who is now deeply critical of the president,” the Democrats concluded.