Even without seeing Robert Mueller's report, or knowing what prosecutors with the Southern District of New York have unearthed, or what congressional investigators will find, we already have witnessed the biggest political scandal in American history.

Historians tell Axios that the only two scandals that come close to Trump-Russia are Watergate, which led to President Richard Nixon's resignation in 1974, and the Teapot Dome scandal of the early 1920s, in which oil barons bribed a corrupt aide to President Warren Harding for petroleum leases.

Mueller has already delivered one of the biggest counterintelligence cases in U.S. history, author Garrett Graff points out — up there with Aldrich Ames (a former CIA officer convicted in 1994 of being a KGB double agent), or Julius and Ethel Rosenberg (executed in 1953 for spying for the Soviets).

one of the biggest counterintelligence cases in U.S. history, author Garrett Graff points out — up there with Aldrich Ames (a former CIA officer convicted in 1994 of being a KGB double agent), or Julius and Ethel Rosenberg (executed in 1953 for spying for the Soviets). Watergate yielded more charges than Mueller has so far: A total of 69 people were charged in Watergate; 48 people and 20 corporations pleaded guilty. Mueller so far has indicted 27 people; seven have been convicted or pleaded guilty.

than Mueller has so far: A total of 69 people were charged in Watergate; 48 people and 20 corporations pleaded guilty. Mueller so far has indicted 27 people; seven have been convicted or pleaded guilty. But historians say that both Watergate and Teapot Dome were more limited because a foreign power wasn't a central player, and a much narrower band of potential offenses was under investigation.

say that both Watergate and Teapot Dome were more limited because a foreign power wasn't a central player, and a much narrower band of potential offenses was under investigation. A fourth notable scandal, the Iran-Contra affair of the mid-1980s — in which arms were traded for hostages held by Iran, with the money used to fund rebels in Nicaragua — also involved a more limited range of issues.

The "biggest" realization might strike Trump supporters as overblown or plain wrong. But consider what we already know about actions of Trump and his associates:

Scandal 1: Trump secretly paid hush money to two mistresses on the eve of his presidential victory, and lied about it. His longtime personal lawyer is going to prison after carrying out the scheme on his behalf.

The historical parallel : Bill Clinton was impeached (but acquitted by the Senate) for lying under oath about an affair with a White House intern.

: Bill Clinton was impeached (but acquitted by the Senate) for lying under oath about an affair with a White House intern. Clinton impeachment Article 3, passed by the House, was obstruction of justice.

Article 3, passed by the House, was obstruction of justice. Earlier presidents, or their friends, had also been known to pay off mistresses.

Scandal 2: During the presidential campaign, Trump confidantes continued negotiating for a tower in Moscow, potentially one of Trump's most lucrative deals ever. He hid this from the public and lied about it. His lawyer is going to prison for making false statements to Congress about the deal.

The historical parallel: None.

Scandal 3: Russian officials had more than 100 contacts with Trump associates during the campaign and transition, including his son, his closest adviser, his lawyer, and his campaign manager. The Russians offered assistance in undermining Hillary Clinton. The FBI and other government authorities weren't alerted about this effort to subvert our election.

The historical parallel: None.

Scandal 4: Michael Flynn was national security adviser at the same time U.S. intelligence officials believed he was compromised by the Kremlin. He pleaded guilty to lying to the FBI about his Russian contacts.

The historical parallel: None.

Scandal 5: Trump fired FBI Director James Comey, and told NBC's Lester Holt it was at least in part because of the Russia investigation: "[T]his Russia thing with Trump and Russia is a made-up story."

The historical parallel: In the "Saturday Night Massacre" of 1973, Nixon tried to stop the Watergate investigation by abolishing the office of Watergate prosecutor Archibald Cox; and accepting the resignation of Attorney General Elliot Richardson, and firing Deputy Attorney General William Ruckelshaus, when they refused to fire Cox.

Scandal 6: Trump overruled the advice of his lawyers and intelligence experts, and granted his son-in-law, Jared Kushner, a top-secret clearance. This so alarmed his White House chief of staff John Kelly that he recorded his opposition in a memo. Trump and his family repeatedly denied he had interfered.

The historical parallel: None.

The big picture: Presidential historian Jon Meacham tells us that this "transcends scandal — it’s a national crisis in the sense of a period of elevated stakes, high passions, and possibly permanent consequences."

"We’re in the midst of making history more than we are reflecting it."

Be smart: Trump himself might survive all of this — and even more. Republican voters seem basically unmoved by the mounting evidence.

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