The Patent Cooperation Treaty (PCT) helps applicants seeking international protection for inventions.

By filing one international application under the PCT, an applicant can simultaneously seek patent protection in  151 other contracting states.

A PCT application doesn’t itself result in the grant of patent rights, since there’s no such thing as an “international patent.” But it does allow the applicant to delay local or regional patent filings and the associated expenses.

The first step is filing an international application with an eligible patent office, called a “Receiving Office.”

At least one physical or legal person (such as a corporation) must be a national or resident of the country in which the Receiving Office is located.

In addition, 29 countries (including the US) have foreign filing license requirements, as summarized  here.

These license requirements can relate to matters of national security.

As the USPTO website  notes,

A license for foreign filing is not required to file an international application in the United States Receiving Office but may be required before the applicant or the U.S. Receiving Office can forward a copy of the international application to a foreign patent office, the International Bureau or other foreign authority (35 U.S.C. 368, 37 CFR 5.1 and 5.11).  A foreign filing license to permit transmittal to a foreign office or international authority is not required if the international application does not disclose subject matter in addition to that disclosed in a prior U.S. national application filed more than 6 months prior to the filing of the international application (37 CFR 5.11(a)). In all other instances (direct foreign filings outside the PCT or filings in a foreign receiving Office), the applicant should petition for a license for foreign filing (37 CFR 5.12)  and if appropriate, identify any additional subject matter in the international application which was not in the earlier U.S. national application (37 CFR 5.14(c)).

Licensing requirements depend on factors such as:

• • The citizenship status of each inventor
  • Where the inventive activity occurred
  • Whether the invention deals with national security or defense

Based on the specifics of the patent and the inventors, it may make sense to obtain a foreign filing license from the USPTO and then file first in a non-US country.