Essentially, a Re-Entry Permit is necessary if you, as a Green Card holder, must be out of the United States for an extended period of time. It is important to remember that a Green Card holder is by definition a United States “Permanent Resident,” and—as the name suggests—Permanent Residents are assumed to permanently reside in the United States. If you are outside the United States for an extended period of time, USCIS can make a presumption that you have abandoned your Green Card.
A Re-Entry Permit will allow you to reenter the United States when you have been absent from the United States for period of more than one year, but less than two years. To apply for a Re-Entry Permit, you must be in the United States. You cannot apply for the Re-Entry Permit from overseas or have the application submitted by your attorney when you are outside the United States.
Having a Re-Entry permit does not guarantee re-admittance to the United States, and USCIS may still take the position that you have abandoned your Green Card. Additionally, if you are inadmissible for some other reason such as a criminal matter, your Re-Entry Permit will not overcome this inadmissibility.
For the purposes of Naturalization, your Re-Entry permit will not substitute for your presence in the United States. The naturalization process has the same residency requirements whether or not you have a Re-Entry Permit.
Your Green Card is a precious asset that should be guarded with care. If you believe you may be out of the United States for an extended period of time, you should consult with your Investment Immigration Attorney.