My father is party member and needs to be supplemented.

As long as you fill in the materials according to the requirements of the Immigration Bureau, there is no need to hide this political background and lie about visa exemption. Just answer the question of seeking truth from facts!

Because party member's status is no longer an obstacle to visas to go abroad, with the increase of exchanges between China and the United States, there are often government and university personnel going to the United States, including party member. The U.S. government did not include the party member in the list of prohibited entry into U.S. territory.

Secondly, political outlook is not a problem in the process of face-to-face signing. You don't usually ask about your political views. If so, you can answer truthfully. Visa officer knows the national conditions of China. If the concealment is verified, they will be rejected. Political background checks are usually conducted.

If you have any questions about the supplementary materials, I suggest you consult a professional immigration agency.