Eu membership would open up borders which would be of benefit to ailing economies of the world nations. The president meets at economic summits yearly to address EU membership which is causation of its importance tot he American economy, as well. Continued US involvement in EU, Turkey could be admitted.
It would not be good for the European Union to allow easier immigration into its borders. Europe would be overwhelmed by immigrants from the middle east and Africa. Unemployment is already very high in southern Europe. Allowing more immigration into the EU would only exacerbate the problem and lead to more conflicts.