The Critical Link between Conditional Green Card & Applying for U.S. Citizenship The N-400 Application to become a U.S. Citizen can be a landmine for Permanent Residents who do not understand the critical link between the I-751 Removal of Conditions and Citizenship process. An N-400 Naturalization Application often resembles an audit. Hopefully, with the help of experienced immigration counsel you will file for Naturalization successfully without delay or surprise