A better question is what do you think that quote means?
Too many people take it to mean that we must fight oppression with violence when such oppression takes hold of our government.
"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants."
But where does it say that the people must spill the blood of tyrants to refresh the tree of liberty?
Instead shouldn't it be a reference to something the founding fathers likely knew, that the citizens of a stable government would become lazy, stagnant. That we would give up freedoms (Patriot Act, etc) because we have taken said freedoms for granted for so long that we cannot contemplate their absence and thus fail to realize as they're slowly taken away.
There is a reason the wise decry MTV culture, decry the constant updating of status' and etc. When people become used to having things done instantaneously they can easily lose sight of the long term and the power of slow change, which though not more powerful than fast change by itself becomes so when ignored.
If you wanted to put the quote to a modern context, it could be said that even now the tree of liberty is being refreshed with the blood of patriots and tyrants, that our state of constant war since WW2 is producing that blood, the blood of our soldiers and the blood of those we perceive as tyrants.
But if you take the quote to have a malicious (or evil) connotation then perhaps these wars are our wake-up call.
These kinds of colonial wars are not new, the same wars have been happening for centuries for the same reasons with the same tactics. It is not beyond reason that the founding fathers would have envisaged this outcome regardless of technology, basic human nature does not change so readily.
So perhaps these wars are the wake-up call, the call to rise out of stagnation not with weapons or violence but to get off our asses and pay attention to what is happening around us rather than what others say is happening.
It's a call to exercise our liberty, which means thinking for ourselves, which means forming our own opinions based on what we have actively gone out and learned from multiple sources. It means that tuning into the evening news should only be a small part of how we learn what is going on in our country, in the world, and most importantly how it relates to us as individuals. It means talking to each other and understanding what problems you have and how you can solve them, not just in the short term but what current events mean in the long term as well.
In my experience quotes such as this, from men such as they, never have a meaning so succinct as the quote itself.