The finger-pointing also takes a page from authoritarians, such as Russian President Vladimir Putin, who systematically seek to sow doubt about democratic institutions that might stand in their way.
"I think it's a disgrace what's happening in our country," Trump said Friday when asked about release of the memo from Republicans on the House Intelligence Committee claiming abuses in the Russia investigation.
"A lot of people should be ashamed of themselves and much worse than that," Trump told reporters.
The president's latest confrontation assails the credibility and impartiality of the nation's justice system, or at least the part connected to the ongoing investigation of Russian meddling in the 2016 election and potentially improper links between Trump associates and the Russian government.
"The top Leadership and Investigators of the FBI and the Justice Department have politicized the sacred investigative process in favor of Democrats and against Republicans — something which would have been unthinkable just a short time ago," Trump wrote on Twitter hours before ordering the release of the formerly classified memo. "Rank & File are great people!"
Never mind that the top leadership of the Justice Department and the FBI are men selected by Trump for those jobs, and never mind that the FBI took the remarkable step of publicly raising "grave concerns" that the memo is skewed and inaccurate.
"The president's attacks on the 'top leadership and investigators' of the Department of Justice and the FBI, like his attacks on the press and the judiciary, appear to be intended to undermine public trust in institutions that may hold him accountable," said John B. Bellinger III, who held a political post as the top State Department lawyer during the George W. Bush administration and was previously a career Justice Department lawyer.
"The president is again elevating his personal interests over the national security of the country," Bellinger said. "If long-term damage to our government is to be avoided, members of Congress and current and former leaders of the Department of Justice must speak up to defend the department and the FBI."
Democrats leaped to do just that on Friday; Republicans not so much.
The memo written by Republican staffers on the House Intelligence Committee outlines what it calls "concerns with the legitimacy and legality" of some FBI and Justice efforts to win court approval for surveillance of a former senior Trump campaign adviser.
The document claims partisan political bias against Trump infected the investigation of the adviser, Carter Page, who is a figure in the broader probe now led by special counsel Robert S. Mueller III. Trump is expected to use the memo to further his repeated claim that Mueller's inquiry is a baseless "witch hunt."
During the campaign, Trump took similar aim at the Republican primary system and the integrity of the election itself.
"Hillary Clinton should have been prosecuted and should be in jail. Instead she is running for president in what looks like a rigged election," Trump tweeted in October 2016, about three weeks before an election his Democratic opponent was heavily favored to win.
Trump's claim that the election was fixed beforehand, and his refusal to say that he would accept the results if he lost, were a challenge to democratic norms unseen in modern politics.
No one should be surprised now by Trump's impulse to attack the legitimacy of perceived opponents, said Brian Fallon, a Justice Department spokesman during the Obama administration and the press secretary for Clinton's unsuccessful 2016 campaign.
"He likes to have a foil, he likes an enemy," Fallon said. "He needs someone to bully, and he needs a narrative so there isn't just scrutiny of him. That's why he tries to keep Hillary Clinton out there," more than a year after the election, "and it's why there is this personification of some kind of 'deep state' " government conspiracy against him, Fallon said.
Questions about Russian meddling in the election and his campaign's dealings with Russian representatives have loomed over Trump's presidency and may now be coming to a head with the Mueller investigation.
Trump's outrage at the probe — "no collusion!" he says at every opportunity — has kept the "rigged system" narrative alive even as Trump appointees take their places in charge of that very system.
Trump tweeted in December that the FBI's reputation was "in tatters." He later unloaded during a campaign-style rally in Pensacola, Fla. "This is a rigged system. This is a sick system from the inside," he said. "And, you know, there is no country like our country, but we have a lot of sickness in some of our institutions."
Sen. Jeff Flake (R-Ariz.), a frequent critic of Trump, took the president to task the same day.
"This is not a sick system, Mr. President, nor is it a rigged system," Flake wrote on Twitter. "Let's not sow distrust in our democratic institutions."
Since then, Trump has asked for loyalty from government officials whose oath is to the Constitution, not the president. The Washington Post reported this week that Trump recently suggested that he should fire Deputy Attorney General Rod J. Rosenstein, the person officially overseeing the special counsel's investigation.
Such complaints, and Trump's repeated attempts to pressure senior law enforcement officials through firings or other means, have now become one of the main focuses of the investigation, The Post reported. That includes Trump's order last summer to fire Mueller, which prompted White House counsel Donald McGahn to threaten to quit before Trump backed down.
Flake's fellow Republican senator from Arizona, John McCain, decried what he called risky partisan attacks on government institutions.
"The latest attacks on the FBI and Department of Justice serve no American interests — no party's, no president's, only Putin's," McCain said in a statement. "The American people deserve to know all of the facts surrounding Russia's ongoing efforts to subvert our democracy, which is why Special Counsel Mueller's investigation must proceed unimpeded," he said.
"If we continue to undermine our own rule of law, we are doing Putin's job for him."
Though Trump is following his own pattern, he is also hewing at least in part to what Russia watchers call a playbook of doubt and division.
Putin's Kremlin has undertaken a systematic effort to corrupt fragile European democracies and meddle in elections as a means to spread Russian influence but perhaps more importantly as a way to delegitimize the very idea of democratic governance, according to scholars such as Russian-born author Masha Gessen.
Even when Russian interference is ham-handed or easily exposed, it serves to erode "public confidence, trust and credibility in democratic systems," Heather Conley, senior Europe scholar at the Center for Strategic and International Studies, wrote in a report called "The Kremlin Playbook."
"There is an undeniable elegance to these 'win-win' tactics for the Kremlin; it is the perfect strategy to erode the foundations of democracy from within, powerfully discrediting the Western model of governance," she wrote.