It is the latest blow to his brother, Boris, whose tenure as prime minister has been marked by successive parliamentary defeats and new-levels of party warfare as he tries to live up to his promise to take the UK out of the EU, with or without a deal, by Oct. 31.

That plan started to go off the rails almost immediately when Johnson (Boris) decided to prorogue parliament, effectively suspending it for five weeks to prevent lawmakers from voting against a no-deal Brexit. While it is normal for parliament to cease work during the party conferences, the extended closure was clearly intended to hammer through his plan. Protests ensued, as well as widespread opposition within parliament itself.

That prompted a rebel group of 21 Tories to join with the opposition to pass a bill to prevent Britain crashing out of the European Union. Johnson (Boris) responded by kicking the Tory rebels out of the party and barring them from running as Conservatives in the next election. The rebels included  Winston Churchill’s grandson, many former government ministers, and the longest serving Tory.

Johnson (Boris) then tried to call a snap election to get control of the party. That effort failed too, as lawmakers insisted on passing a law banning a no-deal exit before agreeing to vote for an election. Under a 2011 law, two thirds of all MPs have to vote in favour of an early general election.

Then his brother called it quits.  Johnson (Jo) was a Remainer, meaning he wanted to stay in the EU, and he wanted a second referendum on Brexit. However, once Boris became prime minister, Jo agreed to his brother’s “do or die” promise to take Britain out of the EU deal or no deal.

But somewhere between the proroguing and the purging and the bombast and the bluster, Jo decided he’d had enough.

The BBC quoted a Downing Street spokesman saying: “The prime minister would like to thank Jo Johnson for his service. He has been a brilliant, talented minister and a fantastic MP. The PM, as both a politician and brother, understands this will not have been an easy matter for Jo. The constituents of Orpington could not have asked for a better representative.”

Rachel Johnson, their sister, who is a newspaper columnist and a Remainer, stuck up for Boris, and claimed that Brexit was not on the menu at family dinners.

The family offers Brits plenty of human interest stories. As Sarah Lyall wrote in the New York Times, the “competitive, tight-knit, look-at-me Johnson clan” holds a place in British life “somewhere in the large, amorphous space between the Kennedys and the Kardashians.”

However, the Johnsons are not the first set of siblings whose political disagreements warrant front-page treatment. In 2010, David Miliband, a former foreign minister, looked set to become the Labour party leader after Gordon Brown lost the 2010 election to the Tories. But he was thwarted by his younger brother Ed, also a politician, who ran against him and won by a razor thin margin. David set off for New York City, where he became the head of the International Rescue Committee. Ed led Labour to an election defeat in 2015, and was replaced by Jeremy Corbyn.

Tolstoy famously wrote in Anna Karenina that “Happy families are all alike; every unhappy family is unhappy in its own way.” It seems the Milibands and the Johnsons are no exception.

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