We the sovereign people are the final arbiters in all constitutional issues. And your quote from the Declaration is our recourse to tyranny per the Founders.
I wish more people would try to pin the Left down whenever they talk about the 2016 election and “the popular vote”, by asking them if they support and defend the Constitution of the United States?
If the answer is yes, ask them if the Electoral College is described in said Constitution?
{it is}.
Then ask them if said Constitution proscribes a way to change it, if they do not like a part of it?
{it does}.
Then ask them if they’ve started the necessary effort to get the popular vote established in the Constitution by the amendment process?
If no, tell them to get started or STFU.