As Donald Trump moves closer to the Republican presidential nomination, unhappy conservatives are contemplating a number of ways to stop him. Some are hoping to stop him at a contested convention in Cleveland in July. But a handful of others have set their sights even further off: In the House of Representatives after Election Day.

It sounds like an outlandish scenario ripped from a script for House of Cards or even Veep. But it’s actually happened before—twice.

The idea got a mainstream boost recently when former New York City Mayor Michael Bloomberg cited it as a reason he wouldn’t run for president as an independent and then when conservative blogger Erick Erickson told NPR that he believes the Republican Party ought to put its weight behind a third-party candidate in order to cause that outcome.

Erickson’s strategy is straightforward, if daunting in practice: The third-party candidate would run to win just enough states that they would deprive both Trump and the Democratic nominee from scoring the majority in the Electoral College (currently 270 electors).