Verified answer

If you by that mean a diplomatic (government) passport, yes you can. However, using a diplomatic passport may not be the best everywhere, especially if you're traveling to countries "hostile" towards your country.

They may question the reasons why you are there.

ok iam from the republic of the marshall islands and I used passport to come to USA. can I use passport to go see my friend in spain for 12 days using my Marshallese passport or do I need to apply for a visas