If they come to take our guns, who do you think?
They already have taken the first shots, multiple times. While not all of them have been firearm-discharges there are notable incidents where they did (Waco, Ruby Ridge)... they have been "taking shots" at our liberties for a long time now.
Why do you think they can have the TSA search anyone flying, despite being restricted from doing so w/o a warrant? Why do you think they can try people multiple times for the same crime by weaseling around and saying the same [set of] actions broke some law [or broke it in a different way]? Why do you think that federal, state, county, and city "Law Enforcement" don't hesitate to enforce statutes/ordinances contrary to their Constitution?