The first, lightest, basic-fucking-step was to start screening people by body temperature at airports. Anyone with an abnormal body temperature is taken into quarantine for a few days. They had three months from November to set it up. (For reference, China almost eradicated the virus in three months from December to Feburary. And South Korea managed to almost completely halt the spread of the virus in that time). Let's look at how that went:
I couldn't find anything from December or November.
January: "Travelers at 3 U.S. airports to be screened for new, potentially deadly Chinese virus"
(https://www.washingtonpost.com/health/2020/01/17/coronavirus...)
Febuary: "CDC considering expansion of airport health screenings for novel coronavirus"
https://edition.cnn.com/2020/02/26/health/coronavirus-airpor...
March (15th): "The US administration has imposed a ban on non-Americans travelling from the 26 European countries in the Schengen free movement zone."
https://www.bbc.co.uk/news/world-us-canada-51895246
March (23rd): "Travelers shocked by barebones coronavirus screening at US airports"
https://nypost.com/2020/03/23/travelers-shocked-by-barebones...
The point is that the United States had three months of advance warning to do something. And they chose to sit on their hands and do nothing. And now 14,696 people have died, and almost 500,000 people are infected. This rate is rapidly rising. What's more, we don't even know if this data is accurate, it is very likely a lower bound given how difficult it is to obtain a test in the United States at the moment (https://www.nytimes.com/2020/03/12/us/coronavirus-testing-ch... | https://www.bbc.co.uk/news/world-us-canada-51860529 | https://www.inquirer.com/health/coronavirus/coronavirus-test...). Again, they had three months of advance warning to set this testing up, within which South Korea had almost nullified the spread of the virus.