Mel Brooks’s Blazing Saddles is the funniest movie ever made. Much of its humor illustrates the devastating stupidity of racism.

There’s a scene early in the movie when the new black sheriff, who has just ridden into town, faces a crowd of racists all pointing guns at him. After the preacher’s bible has a hole shot in it, even he says, “Son, you’re on your own.”

At that point Sheriff Bart points his gun at his own head, takes on two voices — a panicky parody of his own and the mad kidnapper’s — and threatens to kill the sheriff, i.e., himself. Bart then uses his left hand to yank himself into the sheriff’s office still pleading for the townspeople to do what the kidnapper says.

That scene is now being played in the Brexit drama, with Theresa May in the role of Sheriff Bart.

On Friday, shortly after surviving a no-confidence vote in Parliament, May was in Brussels to plead with the EUnuchs for mercy and changes to the Brexit deal she’d negotiated. It’s clear that the deal is about to go down to defeat in Parliament.

May threatened to hold a snap vote in Parliament next week and let her godawful Brexit deal be defeated unless the deal is changed. She reportedly made the threat to the EU’s leaders, German Chancellor Angela Merkel, French President Emmanuel Macron, and EU presidents Jean-Claude Juncker and Donald Tusk.

As she should have expected, they told her to go pound sand. Now she’s back in her office without the help of Mongo and the Waco Kid.

The failure of last week’s no-confidence vote leaves May in office for at least a year. (She has promised not to run for prime minister in the next election in 2020.)

May’s weakness — and the failure to renegotiate anything on the Brexit deal — will result in a cascade of events.

First, May’s Brexit deal will be voted on in Parliament this month or next. When (not if) it fails, May will seek to delay by a year or more the 29 March deadline for Brexit, or just cancel it entirely as an EU court has said she could.

That would bring about a level of UK political chaos unseen since Defense Minister John Profumo diddled around with Christine Keeler in the 1960s.

May is terribly weak but still a somewhat savvy politician. She will want to have a second Brexit referendum next summer to prove what she has always believed in: that the UK should remain in the EU. She will campaign on her own failure to negotiate a decent departure deal as evidence that no good deal can be made.

Her opponents — Labour Party leader Jeremy Corbyn, and a host of conservatives including former London Mayor Boris Johnson — are no stronger than May and will probably find the electorate bored with the whole idea of Brexit.

All of this means that the UK will be as weak as Theresa May at least until their 2020 election. The only good news — at least from the UK perspective — is that Merkel, Macron, and the rest of the EU leaders — aren’t any stronger.