WASHINGTON — Democratic House leaders brushed past the clear reluctance of the special counsel, Robert S. Mueller III, to testify before Congress and insisted on Wednesday that he would be summoned for a House hearing to go over the conclusions of his investigation.
The sight of Mr. Mueller describing his findings on live television deepened Democratic convictions that putting the figure most closely associated with the two-year investigation on the witness stand would help convince Americans of the gravity of Russia’s election interference and President Trump’s efforts to thwart the investigation.
“Given that the president has not been cleared of wrongdoing, and given the seriousness of Russia’s interference in our democracy, I believe that the American people deserve to hear testimony from the special counsel about his report and the report’s conclusions,” Representative Steny H. Hoyer of Maryland, the No. 2 House Democrat, said in a statement after the conclusion of Mr. Mueller’s nine-minute news conference, his first since being appointed.
Representative Hakeem Jeffries of New York, the No. 5 House Democrat who helps calibrate the caucus’s messaging, said he shared that view. Mr. Mueller said Wednesday that he would confine himself strictly to the text of his report and would refuse to opine further.
But, Mr. Jeffries said in an interview, “there is a difference between reading the book and seeing the movie on the big screen.”
That view has put Democrats in a bind as they ponder their next move. Speaker Nancy Pelosi has tried to hold back formal impeachment proceedings against the president, but her vow, repeated on Wednesday, to hold Mr. Trump accountable for his actions can be fulfilled only with a robust, public investigation. And that has yet to gain momentum.
Democratic lawmakers and their aides indicated that they remain reluctant to push Mr. Mueller, 74, too aggressively, either with a subpoena or a public pressure campaign. Representative Jerrold Nadler of New York, the chairman of the House Judiciary Committee, whose staff has been negotiating with Mr. Mueller’s for weeks, sidestepped the matter altogether on Wednesday.
“Mr. Mueller told us a lot of what we need to hear today,” Mr. Nadler said during a news conference in Manhattan. Shuffling through pages of prepared statements, he dodged a question about the use of a possible subpoena to compel Mr. Mueller’s testimony.
Mr. Mueller’s remarks presented House Democrats something of a mixed bag as they continue to pursue investigation of obstruction of justice and abuse of power. Mr. Mueller indicated that he did not relish speaking to Congress and did not see any particular value in doing so. If summoned to Capitol Hill, he suggested that he would go no further than what his office wrote in report, calling the 448-page document “my testimony.”
“There has been discussion about an appearance before Congress,” Mr. Mueller said. “Any testimony from this office would not go beyond our report. It contains our findings and analysis and the reasons for the decisions we made. We chose those words carefully, and the work speaks for itself. And the report is my testimony.”
Mr. Mueller said the decision to speak publicly on Wednesday was his own, as would be his decision to accept or reject an invitation to testify before Congress.
But his remarks also offered proponents of impeachment in the House a new opening to press for a formal impeachment inquiry. And many of the committee chairmen whom Ms. Pelosi has entrusted to lead the investigation of Mr. Trump were eager to hear more from the special counsel.
“While I understand his reluctance to answer hypotheticals or deviate from the carefully worded conclusions he drew on his charging decisions, there are, nevertheless, a great many questions he can answer that go beyond the report, including any counterintelligence issues and classified matters that were not addressed in his findings,” said Representative Adam B. Schiff of California, chairman of the House Intelligence Committee.
Liberal Democrats in the House and those running for president — as well as one Republican House member — seized on Mr. Mueller’s refusal to clear Mr. Trump of wrong doing and his statement that Justice Department policy prohibited charging a sitting president to argue that Congress must.
“If we had had confidence that the president clearly did not commit a crime, we would have said so,” Mr. Mueller said. “We did not, however, make a determination as to whether the president did commit a crime.”
Within hours of Mr. Mueller’s remarks, explicit calls for impeachment proceedings came from 10 of the 23 Democratic candidates for president: Senator Cory Booker of New Jersey; Mayor Pete Buttigieg of South Bend, Ind.; Julián Castro, the former housing secretary; Senator Kirsten Gillibrand of New York; Senator Kamala Harris of California; Mayor Wayne Messam of Miramar, Fla.; Representative Seth Moulton of Massachusetts; former Representative Beto O’Rourke of Texas; Representative Eric Swalwell of California; and Senator Elizabeth Warren of Massachusetts.
Three of them — Mr. Booker, Mr. Buttigieg and Ms. Gillibrand — had not previously called for impeachment.
Representative Val B. Demings, Democrat of Florida and a member of the Judiciary Committee who favors impeachment, said Mr. Mueller’s remarks signaled that only Congress can hold the president accountable.
Representative Justin Amash of Michigan, the lone Republican calling for an impeachment inquiry, said on Wednesday that the special counsel’s oral statement put the onus to Congress to act.
At least one new Democratic House lawmaker, Representative Brendan F. Boyle of Pennsylvania, added his voice to the growing calls for opening an impeachment investigation. By most counts, 35 to 40 members of the 433 current members of the House have supported the idea.
But at least for now, there did not appear to be a broader shift in the caucus. Ms. Pelosi again rejected calls for a hasty impeachment, urging Democrats instead to stay the course on their current investigations and make a judgment later based on public support for removing Mr. Trump from office.
“Nothing is off the table,” she said at the Commonwealth Club of California. “But we do want to make such a compelling case, such an ironclad case that even the Republican Senate, which at the time seems not to be an objective jury, will be convinced of the path that we have to take as a country.”
Most Republicans called again for the House to move on to other issues and let Mr. Mueller enter retirement. Representative Kevin McCarthy of California, the Republican leader, accused Democrats of being focused solely on “satisfying their deep-rooted disdain for the president.”
“Special Counsel Mueller confirmed today what we knew months ago when his report was released: There was no collusion and no obstruction,” said Representative Doug Collins of Georgia, the top Republican on the Judiciary Committee. “Relitigating the 2016 election and reinvestigating the special counsel’s findings will only further divide our country.”