To quell is to overwhelm completely and reduce wholly
to submission, to inactivity, or to passivity. It may be used in respect to
people, to animals, or to things, even immaterial things. You might quell
rioters, fighting dogs, and yes, even an uprising.

Squelch has a slightly different application. Although
Americans use squelch to mean "completely suppress" or "silence" (as in
his spirit could never be squelched), speakers of British English are
more likely to use squelch in other senses: "to drop on something with a
crushing force;" "to fall with a squelch, to make squelching sounds;" or "to
walk or tread heavily in water or on wet ground."

When it comes to uprisings and rebellions, quash might
be as appropriate a word choice as quell. Quash is used for any
summary and decisive extinction or subduing (such as quashing hopes, or
quashing an indictment).

Are you thinking you can’t suppress a rebellion without a
word containing the letter q? Quash that thought. The q-less
crush indicates the utter destruction of effectiveness by heavy ruthless
pressure and force that smashes resistance. The equally q-less
suppress is used to suggest rendering something ineffective or nonexistent
by the power of governmental, legalistic, or social pressure.