• taking an oath, affirmation or other formal declaration to a foreign state or its political subdivisions (Sec. 349 (a) (2) INA) is a potential cause of loss of citizenship if they perform certain specified acts voluntarily and with the intention to relinquish U.S. citizenship.
• when renewing or applying for a US passport, before you sign the form , since in the Acts or Conditions list this will apply to you, you need to line out the part that says “taken an oath or made an affirmation or other formal declaration of allegiance to a foreign state”, and you must provide a supplementary explanatory statement under oath or affirmation by the applicant that you do not wish to relinquish your U.S. citizenship.
• you might have trouble running for public office in either countries or obtaining special security clearances

Disclaimer: I am not a licensed attorney, all information here is gathered only from reading official websites. Please consult your immigration lawyer or consulate for confirmation about these issues before you decide on any course of action.

Yesterday, I decided to do finally complete my paperwork errands for my Mom by going to the Philippine Embassy in Den Haag. And at the same time, I figured, I could inquire more about the visa options that we have in line with our plans to come back to the Philippines and stay long-term.
One thing I noticed about their office is that it is so much better than the one in New York City where there are long lines, noisy crowds, steel bars and glass windows and irritated government workers. Instead, I was greeted by a couple of relaxed women and a nice open office environment. During my visit, there was also a Dutch couple applying for a tourist visa. Basically, the nice lady told me that she strongly advise me to just apply for reacquisition of my citizenship which is by far the simplest for both of us. I told her that my main concerns is the length of time to process it and how it would affect my citizenship status in the US. I found out that it only takes 5 days to process my application for citizenship retention after I submit all the necessary paperwork and also 5 days to process my husband’s non-quota immigration application as well. The good thing about this also is that if we try to setup a business there we could solve the ownership issue easily. She told me that Philippine law recognizes Dual Citizenship. Later that day I found my answers from the website of the San Francisco consulate.

Here is what it says in the website:

Will taking the Oath endanger U.S. citizenship?

No. According to a study prepared by the National Federation of Filipino American Associations (NAFFAA), a person will not lose his/her U.S. citizenship by merely pledging allegiance to another county. Such act can result in loss of U.S. citizenship only if done with an intention to relinquish U.S. citizenship. Since applicants for dual citizenship under this law generally do so with every intention to keep their U.S. citizenship and enjoy the benefits of citizenship in both countries, they are in no way intending to relinquish their U.S. citizenship.

Moreover, NAFFAA assures that American citizenship is not easily lost and is protected under the 14th Amendment of the U.S. Constitution, which states that “all persons born or naturalized in the U.S. are citizens of the U.S. and of the state wherein they reside. No state shall.. deprive any person of life, liberty or property without due process of law.”

U.S. government sources recognize that “dual nationality” or “dual citizenship” can and does occur as a matter of fact, when the laws of the U.S. and another country simultaneously recognize an individual as their citizen.