Declaring War on the Cartels Act of 2023 This bill enhances the term of federal imprisonment for members of certain transnational criminal cartels (i.e., Mexican cartels) who are repeat offenders. It also establishes penalties for U.S. banks and foreign governments that support or otherwise have dealings with these cartels. Specifically, cartel members are subject to an additional 10 to 20 years imprisonment if they are convicted of certain federal crimes (e.g., crimes of violence, fraud, or sexual exploitation) and have been previously convicted of similar crimes (including at the state or local level) within the last five years. Any U.S. national who is convicted as an accessory to such crimes is also subject to up to 15 years of additional imprisonment. The bill also prohibits cartel members from using U.S. banks to conduct business and subjects any related assets to federal seizure. Banks that intentionally do business with cartel members are subject to civil penalties. Additionally, the bill (1) bars noncitizen cartel members and their immediate family from admission into the United States, (2) authorizes sanctions against foreign governments and persons (individuals or entities) that support cartel activity, and (3) requires certain federal agencies to work with foreign governments on combatting cartels. The bill applies to members of the following cartels: The Sinaloa Cartel, The Jalisco New Generation Cartel, The Beltran-Leyva Cartel, The Gulf Cartel, The Los Zetas Cartel, The Tijuana Cartel, and The La Familia Michoacána/Knights Templar Cartel.