Do you have any idea how quick the military and local police would put down an uprising? The military industrial complex and the massive defense apparatus around it has ensured that unless they want it, it will never occur in this country.
You along with many others simply don’t understand the power of the electorate! If you get enough people involved in an uprising, they (we) will prevail!
The local police would be overwhelmed immediately! Most of the military (including the national guard may and probably would) side with the public. The military would also side with the public - we are not a banana republic here - the military has the opportunity to think for themselves.
Only have to look at other countries but with the exception that the military is mostly the public. Yes, they follow orders but they are NOT unable to decide what is Constitutional. As things are going with the Supreme Court, it will be up to the people to decide the ultimate decisions on Constitutionality.
Your post contains only ignorance and fear. First there are many levels of "uprising" most of which cannot be dealt with effectively by any central government except one that has created a fear and distrust level equal to what used to exist in Cuba and currently exists in North Korea. Open opposition might be foolishly premature but there is an entire spectrum of options that precede massed militia. For example, with just a handful of professionals I could create absolute chaos in a large American city - on a sustained basis.
Read up on some of Mao's (and other Communist writers) theories regarding how to position agitation in balance with the opinion and morale of the general population.
Second - I suspect that a large minority to a small majority of rank and file LEO's would not support repression of US citizens - depending of course on how the "uprising" was conducted (random acts of terror would backfire but precisely targeted violence would not). We still have a solid majority of the Marine Corp and a small majority of the Army. The Navy would likely stay neutral. I cannot speak for the Air Force.
I could go on. But fortunately we have an election coming up and we have a long way to go before it comes to open hostilities. If we could just get 30% more of the conservative population off their asses and to the polls we could end it there - at least for a while.