Donald Trump's supporters believed him when he said he was going to "drain the swamp."

Trump's catchphrase tapped anti-Washington views rooted in the exposure of White House deception and corruption during the Vietnam War and Watergate. His was not a new message. In fact, almost every president since Jimmy Carter has made a similar claim to get elected.

The extreme nature of Trump's rhetorical assault on Washington, however, has tempered anti-establishment sentiment among Democrats, reestablishing experience as a desirable quality in a candidate.

Yet Sen. Bernie Sanders' potency, clear in his strong finish in Iowa, reveals that there is still the desire, left and right, for anti-establishment thinking that wants to blow up the system that seems to ignore problems plaguing average Americans.

What many miss is that while touting one's outsider status has become in vogue over the last half century, it means very different things to the two political extremes. Conservatives see Washington, bureaucrats and big government as the establishment that must be tamed, but Sanders, I-Vt., represents a strain of thinking on the left that sees big business as the problem and abhors what they view as the incestuous relationship among Wall Street, K Street lobbyists and Congress.

They believe that such forces have corrupted the Democratic Party in the outsider era, pulling its focus away from the concerns of the poor and the working class.

While the left has largely lost the fight for control of the Democratic Party since 1976, especially over the past three decades, Trump's radicalism also creates an opening for it. Which sides wins the soul of the Democratic Party may determine whether American government is functional moving forward.

Carter was the first man to win the White House by running against Washington, promising to cleanse the stain of Richard Nixon. Carter maintained an outsider's stance for most of his presidency. He looked down his nose at the Washington establishment and its practices, relied on a small inner circle of young Georgia advisers and failed to cultivate relationships with key members of Congress.

This proved disastrous, causing Carter's legislative agenda to run aground and providing an opening for Sen. Edward Kennedy, D-Mass., to challenge the incumbent president for the Democratic nomination in 1980. "This outsider," Kennedy said of Carter, "can't solve our problems. Even on issues we agree on, he doesn't know how to do it."

Kennedy, who had spent nearly two decades in the Senate by that point, had "the contempt of a master machinist for a plumber's helper" regarding Carter, journalist Teddy White wrote.

But Kennedy's challenge was stymied by the Iranian hostage crisis and the Soviet invasion of Afghanistan, and by doubts about his integrity stemming from his role in the death of a young woman on Chappaquiddick Island.

After 1980, the outsider electoral argument remained compelling, and not just for Democrats.

Americans didn't blame a lack of insider knowledge for Carter's failings. It was the opposite: Those running things were corrupt and self-interested, or just incompetent, many believed. This sense enabled Ronald Reagan to argue that government was the problem, and his push for less of it was the solution.

But despite their derisive anti-government rhetoric, the Republicans actually grew the size of government over the next 12 years. That explains, in part, why the establishment was vulnerable to the libertarian-tinged arguments of Ross Perot, whose 1992 candidacy received over 19 million votes, a full 19 percent of the popular vote, as an independent, the most votes of any third-party candidate in American history.

Perot, the idiosyncratic Texas oil man - and in many ways the progenitor of Trump - surged as he castigated Washington as "a town filled with sound bites, shell games, handlers, media stuntmen who posture, create images, talk, shoot off Roman candles, but don't ever accomplish anything."

Bill Clinton, another outsider and another moderate governor of a small Southern state, won that election, defeating Reagan's vice president and successor, George H.W. Bush. Clinton was able to merge establishment connections with an outsider message that borrowed from Perot and from former California governor Jerry Brown, who also ran that year.

"People are mad because they see their problems aren't being solved by Washington, and Governor Clinton offers a way out," Clinton adviser George Stephanopoulos said. "It's Washington's not answering people's real needs."

Clintonism, however, wedded the Democratic Party much more closely to Wall Street, and represents much of what Sanders has been trying to undo during his three decades in Congress. The Democrats began taking corporate political donations much more eagerly in the mid-1980s, and Clinton embraced that approach. Sanders and other progressives believe that compromise has alienated the Democratic Party from the poor and the working class - a critique that Kennedy originated in his challenge to Carter back in 1980.

Yet while George W. Bush's mishandling of Hurricane Katrina, the Iraq War and the economy enabled the next Democratic president, Barack Obama, to claim the outsider mantle, he was no radical outsider who wanted to transform the economy. In fact, many on the left lamented that his stimulus bill addressing the flailing economy in the wake of the 2008 economic crisis was too small and too geared toward tax cuts. They charged that Obama perpetuated and grew bailouts for banks and Wall Street firms, without bailing out average Americans who lost their homes.

The resulting deep wells of populist rage intensified anti-Washington sentiment - on both the right and the left.

Trump tapped into this anger, fusing it with racial resentment and the cultural anxieties of white Christian conservatives. Trump has presided over "a national politics that feels like a debauched rampage of alienation and dysfunction - depraved and degrading, corrupting everyone who goes near it, always finding surprising new ways to reach lower," as Yuval Levin describes in his new book "A Time to Build."

His presidential performance and extreme anti-Washington rhetoric raises an interesting thought experiment: Could Trump be the politician who rescues Washington in the minds of many voters? His radical approach has given the establishment its first opening in decades.

Candidates such as former vice president Joe Biden and Sen. Amy Klobuchar, D-Minn., have stressed pragmatism and government that actually works. Their approach owes to the fact that being anti-Trump means standing for the very things that Trump has tossed aside: time-tested, fact-based processes; deliberation; and a modest, restrained approach.

Even those Democrats who are pushing more outsider messages are fairly conventional politicians. Sen. Elizabeth Warren of Massachusetts, who is running on an anti-greed message and frequently talks about a rigged system, helped create Obama's Consumer Financial Protection Bureau and has been in the Senate since 2012.

Former South Bend, Indiana, mayor Pete Buttigieg, the one front-runner who is truly a Washington outsider, frequently leans into being an outsider, warning that Democrats "cannot take the risk . . . of trying to confront this president with the same Washington mind-set and political warfare that led us to this point." Yet he's also promoting a return to the traditional model of national political leadership. He is a measured, deliberative figure often compared to Obama - and like Klobuchar and Biden, he often stresses moderation.

Even Sanders, a longtime independent democratic socialist who stood outside the two-party system for much of his career, is a creature of the Capitol - one who has worked well with Democratic Party leaders during his decades in Congress.

One of the most surprising details about Sanders is that, unlike Warren, he refuses to come out in favor of abolishing the legislative filibuster.

But Sanders' economic agenda sets him apart as the true anti-establishment outsider, rejecting corporate donations and giving no quarter to big business. He wants to replace all private health insurance with a government-run program, cancel all student debt, and levy a number of taxes on the wealthy and corporate interests.

Sanders' popularity shows that while Trump's recklessness has tempered anti-Washington sentiments among some Democrats, anti-establishment attitudes are still as vibrant as ever on the left. Because for the left, Washington is not the establishment. Wall Street is. And if Sanders is the Democratic nominee, he would work hard to make the case that he is the true outsider, not Trump.

Jon Ward is senior political correspondent for Yahoo News, author of "Camelot's End: The Democrats' Last Great Civil War" and host of the "Long Game" podcast.