George Friedman writes about foreign affairs, here for RealClearWorld. His topic in a word: Brexit. He examines the various arguments that have been raised to counter it, and serially demolishes each. He ends up seemingly on the side of "leave."
Like many observers, Friedman sees the EU as a failed experiment, a sort of geopolitical dead man walking. It doesn't especially work, it isn't democratic, and about all you can say for it is that Europe has experienced no major wars since 1945.
The EU likes taking credit for the "no war" situation but a more realistic analysis suggests peace is the result of the U.S. providing the region's defense since World War II ended. In the absence of large standing national military forces, wars aren't really possible.
As a semi-frequent tourist in Europe, I find the lack of borders and multi-country currency (the Euro) convenient. That never keeps me from going to the U.K. where I still need pounds and have to show my passport. Ditto Switzerland and Norway.
In the absence of a widespread willingness to form a real United States of Europe, with single elected government, unitary fiscal and monetary policy, region-wide military and citizenship, the EU seems somewhat futile to this sympathetic observer. That willingness is nowhere a majority opinion.
I don't know what the Brexit outcome will be tomorrow but I suspect Friedman is correct. Whatever the outcome, the EU is weakened and will go forward looking over its collective shoulder in apprehension.