Every great American scandal follows a similar arc, historians say. One side smells nefarious behavior. The other side contends there’s no there there. Shreds of evidence and whispers of proof energize one side and appall the other. This goes on for a long time.

Sometimes, the scandal talk fizzles out. And sometimes, something comes along that changes everything — the smoking gun.

When Donald Trump Jr. said “I love it” to the prospect of scoring nasty information from friendly Russians about Hillary Clinton in June last year, did that constitute a smoking gun?

In one America, the answer was a pretty solid yes. Slate, Politico, Vanity Fair and some Democrats straight-out declared the president’s son’s email the “smoking gun” in the investigation into whether the Trump campaign colluded with Russia to take down the Clinton candidacy. Many other news organizations hedged a bit, attaching a question mark to the smoldering term.

But in Trump Country, the gun wasn’t smoking — it was just one more toy gun masquerading as the real thing, just one more burst of the same noise that has been cluttering up this presidency since its inception.

Al Baldasaro, a six-term Republican member of New Hampshire’s legislature and an early Trump backer, said on a radio show last summer that Clinton should be “put in the firing line and shot for treason” over her role as secretary of state during the 2012 attacks on two U.S. compounds in Benghazi, Libya.

Now, Baldasaro sees not treason but normal behavior. In politics, he said, “people come to us all the time with stuff on our opponents. . . . I don’t think there’s anything there. It’s a typical witch hunt. Some media are keeping it alive, making money off this.”

Baldasaro called President Trump “an honest guy” and said that “I would bet my last dime he had nothing to do with it. . . . I travel all over the state and have never come across one person who brings up anything about Russia. They don’t care. They don’t think anything happened.”

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From the Teapot Dome scandal of the 1920s through Watergate in the 1970s and the stream of -gates that have followed in the decades since, American political scandals have followed a distinct pattern, said David Dewberry, a professor at Rider University who wrote a book called “The American Political Scandal: Free Speech, Public Discourse, and Democracy.”

“Scandals are stories, cliffhangers that play out in real time,” Dewberry said. “You have two sides, one saying this is not important and the other saying we know there’s documented proof of wrongdoing. With Trump Jr.’s email, this is the point where this scandal has changed.”

But that doesn’t mean that this email is the smoking gun — the one piece of evidence that produces instant consensus that something unacceptably wrong has taken place.

(Victoria Walker,Whitney Shefte,Randolph Smith/The Washington Post)

“This is not the [Watergate] tapes, this is not the blue dress from the Clinton scandal” in 1998, Dewberry said. “We still don’t know from this email if President Trump did anything.”

In today’s deeply divided political landscape, in a society in which information flows with unprecedented speed, “it’s much harder now for us to absorb these key moments,” Dewberry said. The major scandals of the past century took years to play out, and this story might, too.

Many enthusiastic Trump supporters don’t believe the president has done anything terribly wrong. And according to some political observers, even those Trump voters who do believe he acted in concert with the Russians won’t be willing to abandon him until they see an alternative that would maintain Trump’s commitment to upsetting the Washington apple cart.

“They need to hear that nothing Donald Trump has done couldn’t have been done by a President Mike Pence without the drama,” said Robert Leonard, news director at KNIA radio in Knoxville, Iowa. “It’s going to take Fox News to tell them that.”

For now, many Trump enthusiasts in the conservative media are standing with the president — and placing the blame for the rough first six months of the administration squarely on the news media.

“This is not just a story that people are pursuing,” Rush Limbaugh said on his nationally syndicated radio show Tuesday. “This is a lifestyle. This has become a mechanism whereby these people state their identities. They are now defining themselves on the basis of the pursuit of this story. They can’t stop it. They cannot help themselves.”

But Limbaugh hinted that perhaps Trump Jr. was overzealous in taking the meeting with the Russian lawyer. “Junior wanted to be a player,” Limbaugh said. “The thing that’s happening to that family is something that most of us will never experience. . . . Everybody wants to be in on it. Nobody wants to be a straggler. Everybody wants to be considered a player. . . . So Trump Jr. gets the email. ‘Yeah, yeah, I want to help dad, all right, all right, I’ll take it.’ ”

In his 1978 “Political Dictionary,” William Safire, the former New York Times columnist and a speechwriter for President Richard M. Nixon, defined a smoking gun as “incontrovertible evidence — the proof of guilt that precipitates resignations.”

By that definition, the emails that the president’s son released Tuesday cannot be a smoking gun, at least not yet.

But in the operatic structure of political scandals, the “I love it” email might eventually be seen as the first appearance of the prop that turns out to be vital to the denouement of the story.

In most political scandals, the search for a smoking gun fails to result in any such dramatic find. There were no weapons of mass destruction in Iraq. News databases are jammed full of quotations from defenders of Bill and Hillary Clinton through the years, insisting that “there is no there there” regarding allegations about purported scandals in Arkansas, the White House, Benghazi, the Clinton Foundation and the former secretary of state’s email server.

In the early stages of this investigation, “it’s following the pattern of every other major scandal,” Dewberry said. “Waves of publicity about alleged misconduct. Claims that this is nothing. And what tips the argument is when somebody is found blatantly lying, usually to investigators.”

In the Watergate years, the catchphrase was “it’s not the crime, it’s the coverup.” In the Trump-Russia investigation, Dewberry said, if the scandal ever fully erupts, “it will be not the collusion with Russia, but the lying about the collusion with Russia.”

But even if the president’s son had collected incriminating information about Clinton and even if the Trump campaign had then used that against her, some Trump supporters say they would have been fine with that.

“If there was real information about Hillary Clinton that the public needed to know, I understand why that was disseminated if that was the case,” said Robert Jeffress, senior pastor at the 13,000-member First Baptist Church of Dallas and an early Trump supporter who praised the president during the “Celebrate Freedom” concert at the Kennedy Center on July 1.

“What I have followed does not concern me at all,” Jeffress said. “I remain 100 percent committed to this president and his agenda. There has been talk of collusion with Russia for almost a year now and nothing has been proven. What is indisputable is that there is a determined effort by those on the left to paralyze and prevent this president from enacting a conservative agenda.”

Smoking gun imagery entered the lexicon of American scandals in the final stage of Watergate. Defenders of Nixon had repeatedly argued that there was no proof he had obstructed justice in trying to limit the political damage caused by his reelection campaign’s burglary of Democratic Party headquarters at the Watergate office complex. There was, Nixon loyalists insisted, no smoking gun.

Until, of course, there was, in the form of the tape recordings that the president had ordered made of his conversations in the Oval Office. When Rep. Barber Conable, a Republican from New York who had avidly defended Nixon, heard the recording that did the president in, a tape in which Nixon discussed ordering the FBI not to look any further into the Watergate break-in, the lawmaker dubbed that the smoking gun.

[Russian lawyer who met with Trump Jr. has long history fighting sanctions]

The term was coined, according to the Yale Book of Quotations, in Arthur Conan Doyle’s 1894 Sherlock Holmes story “The Gloria Scott.” The great detective, investigating a murder aboard a ship, describes how “we rushed on into the captain’s cabin, but as we pushed open the door there was an explosion from within, and there he lay with his brains smeared over the chart of the Atlantic . . . , while the chaplain stood with a smoking pistol in his hand. . . . The whole business seemed to be settled.”

A quest for a smoking gun was a central part of the public debate during the Iran-contra scandal in the 1980s, when the Reagan administration secretly sold arms to Iran, in violation of a U.S. embargo, and used the receipts from the sales to fund the Nicaraguan rebel group known as the contras.

But most scandals don’t end with a dramatic reveal. An independent counsel’s investigation into Iran-contra dragged on for eight years; eventually, 14 people were charged and President George H.W. Bush issued six pardons, including to his predecessor’s defense secretary and national security adviser.

All of which led Alistair Cooke, the late longtime BBC commentator on American affairs, to say that the eternal hunt for smoking guns was a classic bit of misdirection. “We’ve been conducting the wrong kind of search,” Cooke said in a 1996 piece. “The object in question is the body of the constitution. When we find it with a hundred stab wounds, there’s no point in looking for a smoking gun.”