Lets say that the infection rate is about the same as H1N1 ~ 11% to 21%, and the death rate is 0.77%. There are 327.2 million people in the US, so that would mean 277,138 ~ 529,082 deaths in the US. Those are big numbers, but I bet people wouldn't notice if it was that simple.
However, the truth is this virus is likely more serious then the Spanish flu, because it has such a high hospitalization rate. 20% of people who get it require hospitalization, and unless the number of infected are kept low the system will be overwhelmed. The US is also full of overweight people, and the virus is expectantly deadly to people with diabetes, and heart disease. We have a lot of slobs, and uncouth types, and a healthcare systems, and economy that expects people to go to work sick. There is no reason to expect our death rate to be on the lower end of the globe spectrum.
If the US ends up with a death rate the same as the globe average of 3.4% keeping the infection rate the same it will mean 1,223,728 ~ 2,336,208 deaths.
Without doing any quarantining, and keeping things open and running I think its likely safe to say there would be between 277,138 ~ 2,336,208 deaths from the virus in the US. The real variable we have control over is the infection rate, not the death rate. The average number of deaths from the flu for the last 9 years in the US was ~ 37,461 so on the lower end assuming we do nothing, or all efforts to contain it don't work this seems to be about ten times worse then that.
Have you lost your mind. China has 1.2 Billion people and have only had less than 4,000 deaths. The virus and deaths are already declining in China. I bet less than 500 people die in u.s. from this bug. Sounds like you are fear mongering and listening to, to much CNN.