There is two school of integration deeper and broader, explain it. What view of integration European Union used to expand 1990’s?

“Deep integration” is a term that refers to the dismantling of the border between Canada and the United States. It could affect everything – the economy, social programs, resources and the environment. Deep integration is the harmonization of policies and regulations that govern the foods we eat the items we buy, and how we live. It calls for the formation of a new North America that effectively erases the border between Canada and the United States in the interest of trade north of the border and security concerns south of the border.

Deeper is former economist must adapt their form before moving to the EU. EU uses the broader integration.