Boris Johnson, with the verbal support of Donald Trump, has made a mega-trade agreement with the US a centerpiece of his advocacy for Brexit, with or without a European Union (EU) agreement. His argument is that any losses resulting from the separation from the (EU) would be more than offset by the benefits of a hypothetical agreement that provides the UK with favorable access to the world's wealthiest marketplace.
Trump claims that "We want a very big trade deal" with the UK. However, true to form, he offered no specifics, failed to acknowledge the difficulties of such a deal, and did not address the contradictions and incoherence of his "approach" to trade issues.
What has been consistent since he assumed office is Trump's antagonism to the European Union and his efforts to undermine its effectiveness on issues ranging from Russia, climate change, NATO, trade and Brexit. A skeptic would suggest to Johnson that Trump is merely holding out the possibility of a trade agreement to increase the odds of a non-agreement Brexit and thereby further undermine the unity of the EU.
Assuming Brexit occurs and the UK turns to the U.S. to collect on Trump's "promise" of a very big trade deal, the following is a likely scenario.
The most likely outcome of this very big trade deal is, as Macron put it, the UK's "historic vassalization" to the US, a prospect that haunted Winston Churchill and many others.