If Russian and American geopolitical roles were reversed

I recently read a comment in a blog that said 

"NATO missiles a short flight away is just something that Moscow has to get used to."

Unfortunately, it is more than clear that many members of the U.S. political and media elite share exactly that sentiment.

Now, there is an old and good saying 

"Do unto others as you would have them do unto you."

Let us consider what it would be like if U.S. and Russian roles were reversed.

Here is the hypothetical:

Mexico, Canada, and Cuba all join the CSTO 

https://en.wikipedia.org/wiki/Collective_Security_Treaty_Organization, 

a military alliance with Russia.

Russia indicates that it is worried the U.S. poses a military threat to its allies in North America, so arms them to the teeth.

Hypersonic missiles, cruise missiles, ballistic missiles, fighter-bombers.

All nuclear capable.

All just a short flight time from critical U.S. military facilities and major population centers.

(Think Cuba 1962.)

Obviously, very many in the United States would consider this a huge strategic threat.

How would the U.S. react?

One can't predict exactly, 

but at the very least the U.S. would request that those bordering states remove the weapon systems that directly threaten the U.S.,

and preferably declare neutrality by ending their military alliance with Russia.

I only present this so Americans can perhaps appreciate what Russia is concerned about, 

and develop some sympathy with Russia.