WASHINGTON — The House Judiciary Committee issued two subpoenas on Thursday to compel the former Trump campaign manager Corey Lewandowski and a former White House aide to testify publicly about actions taken by President Trump that could constitute obstruction of justice.
The summons set up another potentially high-stakes public hearing around the findings of the former special counsel, Robert S. Mueller III, when Congress returns next month from its summer recess and seeks to advance a congressional investigation Democratic leaders say could end in impeachment.
Mr. Lewandowski, who has remained a close informal adviser to the president, is viewed by lawmakers as a particularly valuable witness because of his role in an attempt by Mr. Trump in the summer of 2017 to dramatically curtail the special counsel’s investigation of Russian election interference and his campaign. At the time, Mr. Lewandowski enlisted the help of Rick A. Dearborn, the White House aide who also received a subpoena on Thursday.
The two men were ordered to appear at the same hearing, on Sept. 17. But with the White House’s continued opposition to the panel’s work, it may not be easy to secure their testimony. Since the release of Mr. Mueller’s report in April, the Trump administration has successfully prevented the Judiciary Committee from speaking with key witnesses about the episodes of possible obstruction documented in Mr. Mueller’s report.
The new subpoenas could set off more legal fighting between the committee and the White House, but in this case it may be harder for Mr. Trump to block cooperation. Unlike other witnesses, for example, Mr. Lewandowski never worked in Mr. Trump’s government — a fact that significantly limits Mr. Trump’s ability to shield him from Congress.
Representative Jerrold Nadler, Democrat of New York and the chairman of the Judiciary Committee, reiterated on Thursday that he believed Mr. Trump would have been prosecuted based on Mr. Mueller’s findings but for a Justice Department policy that bars indicting a sitting president. He promised more witnesses and hearings could follow in the coming months.
“This will help the committee determine whether to recommend articles of impeachment against the president or other Article I remedies,” he said in a statement. “No one is above the law.”
Democrats want to ask Mr. Lewandowski about his knowledge of the Trump campaign’s contacts with Russians and its views of Russia’s efforts to interfere in the race on its behalf. But their principal interest revolved around meetings he had with Mr. Trump in June and July 2017, shortly after he directed his White House counsel, Donald F. McGahn II, to fire Mr. Mueller, an order Mr. McGahn rebuffed.
In his conversation with Mr. Lewandowski, the president “dictated a message” he wanted Mr. Lewandowski to deliver to the attorney general at the time, Jeff Sessions, according to Mr. Mueller’s report. The message instructed Mr. Sessions, who was formally recused from the matter, to curtail the scope of the special counsel’s investigation to preventing future interference, effectively ending the scrutiny of Mr. Trump’s campaign.
Mr. Trump asked Mr. Lewandowski about the status of the message again a month later. Hours afterward, the president criticized his attorney general in an interview with The New York Times.
Mr. Lewandowski never delivered the message directly to Mr. Sessions, asking Mr. Dearborn, a former Sessions aide, to do so instead. Mr. Mueller wrote in his report that Mr. Dearborn was uneasy about the request himself and also never delivered it.
The subpoena arrives as Mr. Lewandowski is considering entering a Senate race in his home state of New Hampshire. Mr. Trump all but endorsed him Thursday morning, saying Mr. Lewandowski would be “hard to beat” if he got into the race against Senator Jeanne Shaheen, a Democrat. And Mr. Lewandowski is expected to ride with the president in his motorcade Thursday night when Mr. Trump touches down in Manchester, N.H., to hold a rally for his own re-election campaign.
Democrats on the Judiciary Committee are contemplating other subpoenas related to Mr. Mueller’s report as well. When the panel voted to authorize subpoenas for Mr. Lewandowski and Mr. Dearborn, over Republican objections, in July, it also approved summonses for, among others, Mr. Sessions; Rod J. Rosenstein, the former deputy attorney general who appointed Mr. Mueller; John F. Kelly, the former White House chief of staff; and Jared Kushner, the president’s son-in-law and senior adviser.