Subordinate clauses start with a subordinating conjuction, in this case "if". They have subject and verb but do not have meaning on their own as they need the main sentence to complete their meaning.
Subordinate clauses can have different functions in a sentence: adverbs, nouns or adjectives.
In this case, the subordinate clause is acting as an adverb.
The part of the Declaration of Independence is most clearly an example of pathos
is when it calls King George III a “tyrant”. Pathos is an plea to an emotion
and a way of believing the listeners of an argument by creating an emotional answer.