Stop, hey, what’s that sound? Actually, it’s the noise a great political party makes when it loses what’s left of its mind. And it happened — where else? — on Fox News on Sunday, when Mitt Romney bought fully into the claim that gas prices are high thanks to an Obama administration plot.

This claim isn’t just nuts; it’s a sort of craziness triple play — a lie wrapped in an absurdity swaddled in paranoia. It’s the sort of thing you used to hear only from people who also believed that fluoridated water was a Communist plot. But now the gas-price conspiracy theory has been formally endorsed by the likely Republican presidential nominee.

Before we get to the larger implications of this endorsement, let’s get the facts on gas prices straight.

First, the lie: No, President Obama did not say, as many Republicans now claim, that he wanted higher gasoline prices. He did once say that a cap-and-trade system for carbon emissions would cause electricity prices to “skyrocket” — an unfortunate word choice. But saying that such a system would raise energy prices was just a factual statement, not a declaration of intent to punish American consumers. The claim that Mr. Obama wanted higher prices is a lie, pure and simple.