There is a crisis in Spain, as Catalonia wants to secede. I think the U.S. should intervene to avoid negative consequences. If Catalonia secedes, regionalism will occur, and new political entities will likely form. According to the Guardian, Donald Tusk (the president of the European Council), has stated that this will be a disaster for the region, Spain, and Europe. Organizations like the European Union and the North Atlantic Treaty Organization (NATO) will be affected. This will be a gift for Russia, China, and other nations that have discrepancies with the United States.
The same political crisis that took place in Eastern Europe many years ago will take place in Western Europe: A domino effect with painful consequences.
Spain is an ally of the United States
For many years the U.S. and Spain have had a strong relationship, both nations belong to the NATO, and both countries have shared the ideals of democracy and market economy. Spain belongs to the European Union (EU) which protects the values of the Western World. According to The Hill, there are 58 million people in the U.S. that talk Spanish, and its importance keeps growing.
A gift for Russia and China
If Catalonia secedes, many regionalisms will become more aggressive and new nations will appear. Scotland, Basque Country, the North of Italy, and other political divisions will try to be independent.
Will they belong to the European Union and NATO? I think that most new nations will reject it, so, it will become a negative precedent that will erode the power of these organizations. Many countries that are already members of these blocs will leave, and the U.S. will lose powerful allies. Russia has a powerful military and has behaved more aggressively in Europe lately while China has been backing North Korea, so, they will celebrate this chaos.
According to TASS, the Kremlin has been doing military maneuvers with Belarus to ensure their military security. The crisis in Spain is a gift for Moscow and its allies.
No reason to secede
The Catalans have been complaining a lot about Spain, but the reality is that Catalonia has been able to grow economically while it's been part of the Iberian country.
The Catalans have had a lot of political freedom, they have been able to travel to foreign countries, they have had religious freedom, and more. They haven't experienced the same level of oppression that Lithuanians and Ukrainians had to experience under the Soviet regime. The Catalans have to stop their irresponsible behavior, and the U.S. has to side with Spain to protect the Western World.