Theresa May to offer Parliament new Brexit deal with vote on 2nd referendum

British Prime Minister Theresa May said Tuesday that she would offer lawmakers "a new Brexit deal" that — if passed — would also include a vote in Parliament on whether to hold a second referendum.

Why it matters: Holding a second referendum has long been a red line for May, who has staked her entire premiership on delivering the results of the 2016 Brexit vote. Now, in a last-ditch effort to salvage Brexit before stepping down as prime minister, May is offering lawmakers a potential chance to put it to the people in exchange for passing her deal.

Details:

• May's new bill will put the government under a legal obligation to prepare alternative arrangements for the Irish border by December 2020 to prevent the much-maligned backstop from coming into effect.
• The Northern Ireland Assembly will have to give consent for any deviation away from the mainland, ensuring that the U.K.'s single market remains aligned.
• The bill will give Parliament control over future trade negotiations with the EU, satisfying a key demand from the opposition Labour Party.
• Parliament will also get to vote on whether to adopt a temporary customs union with the EU.

How it's playing: Members of the European Research Group — the hardline Brexiteer faction of the Conservative Party that has helped block May's deal 3 times — aren't likely to back the deal. The DUP, the Northern Ireland unionist party that props up May's government, also doesn't appear to be convinced.

• Even the People's Vote, which has long advocated for a second referendum on a final Brexit deal, said in a statement: "Today she tried to spice up the same old deal with a series of supposedly new concessions, but then admitted she had no way of guaranteeing that she could deliver any of them."

What to watch: May will likely be forced to resign if she can't get this deal through.

Go deeper: Everything you need to know about Brexit