As I read the his sentence, it appears as if he defines four “truths” which are self evident... 1. All men are created equal, 2. they are endowed, by their creator, with rights, among which are life, liberty and the pursuit of happiness, 3. governments are established to secure those rights and 4. if that government becomes oppressive, the people have the right to abolish it and form a new one that isn’t. It is rather odd, to me, that the first two rights begin with “thats” which are not capitalized, but the second two “thats” are capitalized even though, grammatically, the sentence has not ended.
There are 4 truths, but only 3 rights: Life, Liberty, and Happiness. The rights are capitalized.
If the founders thought that we could make up new rights, they would have stated in the next sentence:
That to secure these rights and others, governments are instituted among men ..."
Instead of:
That to secure these rights, governments are instituted among men..."
The only rights mentioned are ONLY the 3 from the previous sentence.
See the text:
http://upload.wikimedia.org/wikipedia/commons/0/07/Us_declaration_independence.jpg
"We hold these truths to be sacred & undeniable; that all men are created equal & independant, that from that equal creation they derive rights inherent & inalienable, among which are the preservation of life, & liberty, & the pursuit of happiness; that to secure these ends, governments are instituted among men, deriving their just powers from the consent of the governed..."