It doesn’t take much to launch a political coup — just ask any tin-plated dictator of a banana republic. They’ll happily tell you that it requires only four simple steps.

1. Have a moron elected as the leader of the nation. This can be accomplished by preying on the weak-minded dependent class and the sanctimonious socialist myrmidons (typically found teaching at universities or working for non-profit community-organizing groups) that engage in socialist group-think. Simply by promising them “hope” or “change” (or both) you will quickly gain their mind-numbed, zombie-like support.
2. Have said moron install and then direct an equally-incompetent leader of the Secret Police to release a report indicating that your political enemies (or people that probably didn’t vote for the moron you report to) are committing “crimes against the state” when they’re actually engaging in lawful activities. It further aids your cause to paint these people as “rednecks”, “hicks”, “racists”, or people that “cling to their guns or religion”. It’s especially useful if you include in this group all people with the will and/or ability to resist your tyranny, such as military veterans or gun owners, and those with principles, such as those that oppose abortion. Be sure to label them something vile, like “domestic terrorists” in order to invoke the emotional response of the aforementioned weak-minded dependent class and sanctimonious socialist myrmidons.
3. Have the incompetent leader of the Secret Police further direct an “escalation” of the policy of reporting family, friends and neighbors to the secret police. This is a timeless technique that has proven its worth time and time again. Search for glorious tales of Joseph Stalin or Adolph Hitler to see the stunning effectiveness of this simple technique.
4. Once a sufficient database is complied and contains sufficient trumped-up information on your political enemies, you should accuse your political enemies of engaging in “crimes against the state” for their participation in lawful activities. After the accusation, it’s a simple matter to jail them and confiscate their weapons and property, thus ending the threat to your political coup and allowing you to install a communist form of government.

The only issue still in question is whether the moron installed as the leader of the nation can trust the motives of individual or group financing the coup — if they’re willing to finance the overthrow of a government, they’re perfectly willing to throw the useful idiot installed as leader of the nation under the bus once their usefulness has been outlived.

But this discussion is purely academic — something like this could never happen in the USA.