Why do Republicans act like the Founders were some monolithic bloc who all believed the same thing, when they were in fact as ideologically diverse as Congress today? What did Patrick Henry and Alexander Hamilton have in common, other than not wanting to be ruled by King George? No, "the Founders intended" is just code "I'm going to make up a justification for my already-existing opinions."
Secondly, the nation that the Founding Fathers wasn't great. Sorry, Founding Fathers, but you didn't built that. Future patriots like William Lloyd Garrison, Abraham Lincoln, Susan B. Anthony, William Jennings Bryan, Theodore Roosevelt, Franklin Roosevelt, Martin Luther King, Lyndon Johnson, and Barack Obama made that happen.
Even though they were in the 18th century, the founding fathers did have a 20th century liberal, Thomas Paine.