WASHINGTON — House Intelligence Committee chairman Adam Schiff said Sunday that his panel has reached an agreement to secure testimony from the anonymous whistle-blower whose detailed complaint launched an impeachment investigation into President Trump.
The announcement from Schiff came on the same day that Tom Bossert, a former Trump homeland security adviser, delivered a rebuke of the president, saying in an interview on ABC’s ‘‘This Week’’ that he was ‘‘deeply disturbed’’ by the implications of Trump’s recently reported actions.
Those comments come as members of Congress return to their districts for a two-week recess, during which they will either make the case for Trump’s impeachment or defend him to voters amid mounting questions about his conduct.
In appearances over the weekend, House Speaker Nancy Pelosi, Democrat of California, offered a preview of the Democratic message, casting the impeachment inquiry as a somber task that she chose to endorse only as a last resort.
‘‘I have handled this with great care, with great moderation, with great attention to what we knew was a fact or what was an allegation,’’ Pelosi said Saturday at the Texas Tribune Festival in Austin. ‘‘This is very bad news for our country, because if as it seems to be, our president engaged in something that is so far beyond what our founders had in mind.’’
While privately favoring a rapid probe confined to the Ukraine allegations, Pelosi said Saturday it would last ‘‘as long as the Intelligence Committee follows the facts.’’
On a conference call with House Democrats on Sunday afternoon, Pelosi told her colleagues that public sentiment — something she had frequently cited as an obstacle to pursuing impeachment — had begun to swing around.
‘‘The polls have changed drastically about this,’’ she said, urging a careful approach, according to notes taken by a person on the call: ‘‘Our tone must be prayerful, respectful, solemn, worthy of the Constitution.’’
In an appearance on ABC News’s ‘‘This Week,’’ Schiff, Democrat of California, echoed Pelosi’s message. He also said he expected the Intelligence Committee to hear from the whistle-blower ‘‘very soon,’’ pending a security clearance from acting director of national intelligence Joseph Maguire.
‘‘We’ll get the unfiltered testimony of that whistle-blower,’’ Schiff said, noting that Maguire said in a hearing Thursday that he would allow the whistle-blower to testify privately without constraints.
One of the whistle-blower’s attorneys, Mark Zaid, said in a statement that bipartisan negotiations in both chambers are ongoing ‘‘and we understand all agree that protecting the whistle-blowers’ identity is paramount.’’ He added that no date or time has been set.
Most Republican lawmakers and White House aides, meanwhile, continued to voice support for the president, even as they faced grilling by hosts on Sunday morning news shows over their efforts to discredit the unidentified whistle-blower and keep the focus on former vice president Joe Biden and his son Hunter Biden.
Representative Jim Jordan, Republican of Ohio, pointed to an initial finding by the intelligence community inspector general stating that while the complaint was credible, the whistle-blower had an ‘‘arguable political bias.’’
“He had no firsthand knowledge. . . . And, second, he has a political bias,” Jordan said on CNN’s ‘‘State of the Union.’’ ‘‘That should tell us something about this guy who came forward with this claim.’’
White House senior adviser Stephen Miller went even further in an at-times heated interview on ‘‘Fox News Sunday.’’ Miller dodged several questions from Chris Wallace about allegations surrounding the president’s actions, such as Trump’s decision to use not the federal government but rather his personal attorney Rudy Giuliani to obtain information on the Bidens’ activities in Ukraine.
He also declined to answer when asked by Wallace to outline how, in his view, the Bidens broke any laws. And he disputed the use of the word ‘‘whistle-blower’’ to describe the person who sounded the alarm about Trump’s actions, arguing that the complaint was a ‘‘partisan hit job’’ by a ‘‘deep-state operative“; Maguire said in congressional testimony last week that he thinks the whistle-blower ‘‘is operating in good faith and has followed the law.’’
As both sides sparred, Trump largely stayed out of public view. The president spent the weekend playing golf at his club in Sterling, Va. On Sunday morning, he sent more than 20 tweets and retweets slamming Fox News Channel host Ed Henry’s performance during a segment with conservative commentator Mark Levin.
Later Sunday, Trump tweeted that he wants Schiff ‘‘questioned at the highest level for Fraud & Treason’’ for his remarks at last week’s hearing in which Maguire testified. And Trump demanded to meet the whistle-blower as well as the person’s sources.
‘‘In addition, I want to meet not only my accuser, who presented SECOND & THIRD HAND INFORMATION, but also the person who illegally gave this information, which was largely incorrect, to the ‘Whistleblower,’ ‘‘ Trump tweeted. ‘‘Was this person SPYING on the U.S. President? Big Consequences!’’
On Sunday night, ‘‘60 Minutes’’ tweeted: “ ‘60 Minutes’ has obtained a letter that indicates the government whistleblower who set off the impeachment inquiry of President Trump is under federal protection because they fear for their safety.’’
House Democrats last week began an impeachment inquiry into Trump’s actions after the release of the whistle-blower complaint as well as a rough transcript of a July phone call in which Trump repeatedly urged Ukrainian President Volodymyr Zelensky to investigate Biden.
Hunter Biden served for nearly five years on the board of Burisma, Ukraine’s largest private gas company, whose owner came under scrutiny by Ukrainian prosecutors for possible abuse of power and unlawful enrichment. The former vice president’s son was not accused of wrongdoing in the investigation.
As vice president, Biden pressured Ukraine to fire the top prosecutor, who Biden and other Western officials said was not sufficiently pursuing corruption cases. At the time, the investigation into Burisma was dormant, according to former Ukrainian and US officials.
Trump’s handling of the matter appears to have alarmed voters. An ABC News-Ipsos poll released Sunday showed that 63 percent of adults say it is a serious problem that Trump pushed Zelensky to look at Hunter Biden.
Among those expressing concern Sunday was Bossert, a rare official with ties to Trump who has taken on the president.
Bossert said he was ‘‘deeply disturbed’’ by the implications of Trump’s call to Zelensky and strongly criticized the president for seemingly furthering an unfounded theory that cybersecurity firm CrowdStrike played a role in shielding e-mails sent by Trump’s 2016 Democratic opponent, Hillary Clinton, and circulating allegations of Russian hacking.
The US intelligence community has concluded that the Russians did hack Democratic sources in an effort to swing the election to Trump.
‘‘That conspiracy theory has got to go,’’ Bossert said on ABC News’s ‘‘This Week,’’ explaining that Trump was motivated to spread the ‘‘completely debunked’’ theory because he had ‘‘not gotten his pound of flesh yet’’ over accusations that he had Russian help in winning the 2016 election. ‘‘They have to stop with that. It cannot continue to be repeated in our discourse. . . . If he continues to focus on that white whale, it’s going to bring him down.’’