U.K. Parliament approves snap general election on Dec. 12

LONDON — The U.K. will go to the polls with Brexit still in the balance, as Parliament cleared the way Tuesday evening for a snap general election on Dec. 12.

Why it matters: Prime Minister Boris Johnson stormed into office three months ago vowing to deliver Brexit by Oct. 31, but was thwarted by a Parliament that remains hopelessly deadlocked amid the current political crisis. Johnson believes he can break that deadlock by winning a majority in December, but a loss could render him one of the shortest-serving prime ministers in history.

Catch up quick: Johnson attempted on Monday — following the EU's move to extend the Brexit deadline yet again, to Jan. 31 — to schedule a December election while leaving open a window to pass his Brexit plan before then.

• After that attempt failed, he put his Brexit plan on ice and aligned with two fiercely anti-Brexit opposition parties, the Liberal Democrats and the Scottish National Party, who were also calling for a December vote.
• Together they outflanked the Labour Party, which has been struggling in the polls amid a split over Brexit and under Jeremy Corbyn's unpopular leadership.
• The latest: With the writing on the wall, Corbyn also backed a December election and the bill passed 438-20. Parliament is expected to dissolve next week to make way for the campaign.

Current polls (FT poll tracker):

• Conservatives (35%), Labour (25%), Liberal Democrats (18%), Brexit Party (11%).
• Regional parties in Scotland, Wales and Northern Ireland have less support nationally but are also expected to win seats.

What to expect: Johnson will run as the man who'll make Brexit happen, aiming to win over pro-Brexit voters in the North of England who have historically backed Labour.

• He needs to win seats in the Labour heartland to make up for losses in Scotland and greater London, where Brexit is unpopular.
• The insurgent Brexit Party could take votes from both parties — Conservative voters who endorse a more hardline vision of Brexit, and Labour voters who want Brexit but don't want to vote Conservative.
• The Liberal Democrats, meanwhile, have gained support (mostly at Labour's expense) on the back of their plan to block Brexit altogether.

Behind the scenes: Internal polling and focus groups have Downing Street feeling confident, a source briefed on the matter told Axios.

• But the Conservatives were also flying high ahead of a snap general election in 2017 that ultimately proved disastrous for then-Prime Minister Theresa May.
• Corbyn exceeded expectations in that election and has survived longer as opposition leader than most anticipated. Despite record-low approval ratings, he now has an opportunity to become prime minister.
• If Labour loses, the party could soon be searching for a new leader and a new political identity.

The bottom line: Conventional wisdom in Westminster is that Johnson is likely to win, though perhaps not with the big majority some Conservatives are hoping for. But the U.K.'s recent political history suggests we should be prepared for the unexpected.

• Worth noting: This will be the U.K.’s first December election since 1923.
• Go deeper: Everything you need to know about Brexit