The Prime Minister wants a clean break with the EU bloc. Most importantly, this will mean Britain leaving the single market. It is the "hard Brexit" that Nigel Farage, the right-wing press and many of her Conservative MPs wanted -- and that many of the 16,141,241 people who voted Remain feared
Britain also will give up its full membership in the EU customs union -- spelling higher tariffs for UK exports to the EU -- but could remain as an associate member. That negotiation starts now.
May's 12-point "Plan for Global Britain," unveiled in central London on Tuesday, provides more detail than had been expected in Westminster. Now she has to persuade other EU leaders to accept it.
The Prime Minister will be cheered on by pro-Brexit British newspapers and Tory MPs who are overjoyed with her plan because Britain will save billions of pounds by no longer contributing to the EU budget and can close its doors to immigrants by giving up freedom of movement.
May acts as if her negotiating hand is strong and talks of a "new and equal partnership" with the EU. One of the key phrases from her speech was that "no deal is better than a bad deal" -- if EU leaders do not accept her terms, she will walk away.
Basking in praise from anti-EU populists, she has a false sense of security in her own position. This is a dangerous place to be.
Walking away from a "bad deal" would mean no free trade deal with the EU, which would be punishing for British businesses, the City of London and the wider UK economy. The short-term sense of triumph that the Prime Minister and the pro-Brexit camp feel now will likely turn into long-term pain for the UK economy.
Crucially, May underestimates how dimly Germany and France view Britain's exit from the EU and with it the withdrawal from the post-war dream of European harmony and political unity.
The Leave side says that no matter what happens, however bumpy the negotiations between the UK and Brussels will be, Germany will still want to sell its cars to the UK, as will France its wine. Trade will win out.
Yet this is not how Germany's Angela Merkel sees Brexit. Germany and France -- for now, led by a pro-EU president -- will not reward the UK for leaving the EU. In fact, they are likely to impose tariffs on UK trade as a price for leaving.
That post-war dream of European unity has always been more important to Germany and France than it has to the British public. The European "superstate" that populist politicians like Nigel Farage have spent years claiming was the ultimate goal of the EU is one of the main reasons ordinary Britons voted Leave.
Yet it is also the very reason why Merkel and her fellow EU leaders will be willing to play hardball with May in the coming months.
When it comes to preserving the EU project, politics will trump economics.