Please identify the group that will oppose them.
While we wait for PWTS to respond, let me offer my answer:
It comes in two parts:
You. See your words in the 3d sentence of your FR profile:
...you have to be unceasingly vigilant against all of the bad people who want to imperil your peaceful home, family, and way of life.
The second part comes from the Constitution; the 2d Amendment:
A well regulated militia, being necessary to the security of a free state...
Now you may not feel very well regulated, but many of us do and are.