Spain Unhappy with Iran's Uranium Enrichment

This leaked cable (classified) from February 19th of last year conveys a message passed along from Spanish officials to the United States that Iran "crossed a line" after the announcement that the country planned to begin enriching uranium up to 20%.

Some Questions:

Does Spain's status as a non-nuclear state legitimize its anti-proliferation stance?

Why did Spain feel the need to convey its mood to the US? Can they pursue nonproliferation in Iran without the United States? Might US involvement hinder Spain and the EU's ability to succeed in such efforts?