I think this whole "ban the CCP" debate is fueled by a misunderstanding about how immigration law works. Currently, under the Immigration and Nationality Act, the principle mechanism to decide whether a person is "qualified" for a nonimmigrant visa is section 214(b) of the INA: "Every alien shall be presumed to be an immigrant until he establishes to the satisfaction of the consular officer, at the time of the application for admission, that he is entitled to a nonimmigrant status". This means that the burden is on the visa applicant to prove they are qualified.

In addition, there are dozens of statutes that are called "ineligibilities". These are specific provisions which may permanently or temporarily disqualify a person from receiving certain types of visas (or "ban" them, if you will). Some examples include: anyone who has ever been convicted of certain crimes, anyone who has ever done drugs, anyone who has ever lied to a U.S. official to gain a benefit, etc. The U.S. government adds and removes certain types of ineligibilities periodically.

Until the Immigration Act of 1990, you could be denied a visa or deported from the United States for being a member of the Communist Party or any other totalitarian party. This was a product of legislation introduced in the Internal Security Act of 1950 and then codified in various "Red Scare" era immigration legislation subsequently. After 1990, most of the nonimmigrant visa restrictions were removed, and currently there are restrictions on communist party membership only in the green card and citizenship process. See INA 212(a)(3)(D): "An immigrant visa applicant who is or has been a member of, or affiliated with, the Communist or any other totalitarian party (or subdivision or affiliate thereof), domestic or foreign, is ineligible under INA 212(a)(3)(D) unless qualifying for one of the exceptions described in 9 FAM 302.5-6(B)(5) below. *Nonimmigrants are not subject to the provisions of INA 212(a)(3)(D)."* (emphasis mine) https://fam.state.gov/FAM/09FAM/09FAM030205.html

Alright, whew, getting long here so I will get to the point. The mechanism that will most likely be used to "ban" CCP members and their families will be an Executive Order which modifies 212(a)(3)(D) to once again apply to nonimmigrants (tourists, business travelers, students, etc). This will not prevent them from obtaining visas for the most part. It will require, however, that they admit they are members and request a waiver of the ineligibility. I have no insider knowledge of this process, but if we use the "Muslim ban" as a template for how this might work, you may see something like this included in the EO:

"Waivers are available to people who can show that (1) denying entry to the U.S. would cause the visa applicant undue hardship, (2) entry to the U.S. would not pose a threat to the national security or public safety of the U.S., and (3) entry would be in the national interest of the U.S."

This will allow the U.S. government discretion to admit the people that they prefer, allow them to gather information on party membership, and open the applicant up to criminal liabilities later on for visa fraud if they misrepresent their membership. It will use an existing process already in place to process these waiver requests, and probably extend processing time a fair bit (weeks to months). It will be a fairly large administrative undertaking, but it is not dissimilar from programs like EVUS which already specifically target Chinese travelers.