Can a European(Portuguese) fellow become a police officer in USA?

You do not have to have a college degree to become a US citizen but you do have to meet quotas in immigration in order to get a visa as a potential permanent resident and then there is a waiting period before you can apply for citizenship plus you must be sponsored and have a job so it is not as easy as just showing up and applying for a job. Once you have that problem solved then you can contact any police department you think you might want to work for and ask what the requirements are.