For Boris Johnson, this is a classic good news/bad news scenarioThe good news: Nigel Farage will indeed prevent any Brexit Party challenge in the 317 constituencies that Johnson’s Tories now hold in Parliament. The bad news: Farage intends to fight in all other constituencies, which means the Brexit vote may well be split in seats Johnson needs to pick up in order to get a majority:

Britain’s euroskeptic Brexit Party said it wouldn’t contest hundreds of Conservative Party-held districts in next month’s U.K. election, boosting Prime Minister Boris Johnson’s chances of re-election.

Brexit Party leader Nigel Farage said his upstart party wouldn’t field candidates in 317 seats won by the Conservatives in the 2017 election to avoid splintering the pro-Brexit vote and paving the way for anti-Brexit parties to form a coalition to call another referendum.

“I think our announcement today prevents a second referendum from happening,” Mr. Farage said. “That is the single most important thing for our country.”

That’s undoubtedly a win for Johnson in the short run. It’s unclear how strong the Brexit Party will run in the elections next month, but even a nominal showing could have spelt disaster for Tory incumbents in tight races. Farage’s tactical retreat in those standings will mean an easier road to re-election.

However, it gets complicated after that. Of the other seats in Parliament held by Labour and other “Remainer parties,” as Farage puts it, his party “will stand up and fight them all.” The Commons has 650 seats, which means that it takes 326 to get to a majority. Johnson needs nine more seats than he has now, and he will need to get those from seats currently held by Labour, Liberal Democrats, or the Scottish National Party, which seems unlikeliest for gains. If Farage’s Brexit candidates run in those elections, it’s very possible that they will split the Brexit vote in the most competitive constituencies and prevent any chance of Johnson getting an outright Tory majority.

What happens if Farage’s party wins seats, which also seems unlikely given the turf over which he’ll be fighting? Those would add to Johnson’s total in Parliament and could give him a majority coalition. That too would be problematic, however; it would mean the end of Johnson’s deal with the EU and a return to the “hard Brexit” option, as Farage could then directly block Johnson’s deal with the EU. That would lave Parliament utterly stuck on the Brexit issue … again.

Complicating this question is Labour’s true intentions with Brexit. As Farage notes above, Labour had promised to facilitate a good deal and then put it up for a second referendum. In the election, however, nearly half of his MPs have pledged to fight Brexit entirely if re-elected:

JEREMY CORBYN could be facing another Brexit crisis after 116 Labour Party candidates signed a general election pledge saying they will campaign to Remain in the European Union if elected as an MP.

Jeremy Corbyn’s Brexit policy has been repeatedly called into question, as he has already vowed to give Brits another say on leaving the European Union. Mr Corbyn has said if he is elected in the December 12 vote he will negotiate a fresh deal with the EU – before putting that back to the British people within six months. But, the Labour Party leader has not yet clarified in the lead up to that potential second referendum, whether he would support his newly agreed deal – or fight to Remain in the bloc.

The Labour Party said a “special conference” would be held in that circumstance before another referendum which would “decide how the party would campaign”.

However, 116 Labour parliamentary candidates may have already jumped the gun, after pledging to fight to Remain in the EU, likely regardless of any deal that is reached.

Labour wants to eat its Brexit cake and have it too, which is not going to be sustainable in an election called to deal with the Brexit crisis. Voters will want a real choice in the election, not muddled and contradictory policies. They might find themselves spit out by voters for being lukewarm, professing neither hot nor cold on the main question of the day, rendering their credibility suspect at the decision point.

Still, having Farage’s tacit electoral support isn’t bad news for Johnson. He’s likely to remain Prime Minister, barring some sort of disaster between now and the election, without the internecine fight Farage threatened until now. But who he’ll owe, and what that means for his deal, is still very much an open question. Ask Theresa May how her partnership with the DUP worked out.