Republican presidential nominee Donald Trump announced his ethics overhaul plan on Monday, pledging to “drain the swamp” in Washington.

Since the nation’s capital was built on a literal swamp, the phrase has become a staple for political outsiders, promising to come to Washington and clean up a mess.

The phrase first became popular in 1983 when President Ronald Reagan said he was in Washington “to drain the swamp,” a reference to limiting the reach and growth of government.

I will Make Our Government Honest Again — believe me. But first, I’m going to have to #DrainTheSwamp in DC. https://t.co/m1lMAQPnIb

— Donald J. Trump (@realDonaldTrump) October 18, 2016

Similarly, before House Minority Leader Nancy Pelosi became speaker in 2007, she spoke of having to “drain the swamp” after more than 10 years of GOP House control. And she said she would start by trying to “break the link between lobbyists and legislation.”

The metaphor was used again when Ben Carson, now a Trump surrogate, released an ad last year during his Republican presidential campaign that opened with him saying, “Did you know Washington is built on a swamp?”

Of course, reining in special interests has usually been easier said than done in Washington.

When President Barack Obama first came into office, he instituted a rule that barred presidential appointees from seeking lobbying gigs while he was president. He also said former lobbyists would not be able to get jobs in the administration.

However, his former intellectual property czar Victoria Espinel is now president of The Software Alliance.

If Trump wants to see a perfect example of the swamp, he can look no further than his adviser, former House Speaker Newt Gingrich. While not a lobbyist, Gingrich was paid $1.5 million by mortgage agency Freddie Mac.