Upon arriving at Joint Base Andrews in Washington on Thursday, the president said "there should be a way" to stop investigations into his communications with Ukraine President Volodymyr Zelenskiy.
The president, speaking to reporters, suggested he may consider legal avenues to block Democrats on Capitol Hill.
"What these guys are doing -- Democrats -- to this country is a disgrace and it shouldn't be allowed," Trump said. "There should be a way of stopping it. Maybe legally, through the courts."
The White House did not comment on the president's suggestion.
Trump began his day venting his frustration while at a private event, saying, according to an audio recording obtained by the Los Angeles Times, that the whistleblower was "almost a spy."
"I want to know who's the person, who's the person who gave the whistleblower the information? Because that's close to a spy," Trump continued. "You know what we used to do in the old days when we were smart? Right? The spies and treason, we used to handle it a little differently than we do now."
Not long after the hearing with Joseph Maguire, acting director of National Intelligence, ended on Capitol Hill, the president attacked it as a "disgrace" and a "witch hunt."
"Here we go again," Trump said.
When Marine One touched down on the South Lawn on Thursday, the president made a beeline to cheering supporters and ignored questions shouted by media members. In the past, the president has often been defiant in the face of controversies and appeared eager to spar with reporters' questions. But this time, the president chose to retreat into the White House alone. With a wave, he walked down the colonnade and into the Oval Office. A few minutes later, he sent off a tweet and singled out Democratic Chairman Adam Schiff.
"Liddle' Adam Schiff, who has worked unsuccessfully for 3 years to hurt the Republican Party and President, has just said that the Whistleblower, even though he or she only had second hand information, 'is credible,'" Trump tweeted. "How can that be with zero info and a known bias. Democrat Scam!"
Later in the afternoon, under gray skies, the president made an unexpected appearance on the steps of the White House. Law enforcement officers shouted, "We've got your back, Mr. President!" at a photo op on the South Portico.
After the president accepted an award, he spoke of progress on the border, then shook the hands of the smiling officers.
"Hang in there, Mr. President," one said, and Trump walked into the White House alone, holding a small, gold plaque.