My extremely narrow minded friend posted a picture of mt Rushmore titled "ever wonder why there are no democrats on my Rushmore? Yeah me neither". Id like to educate him.
One comment mentioned jefferson was sorta one but when i looked into it it seemed like he simply started his own party to combat hamiltons.
Washington steadfast Y refused any party identification. Jefferson is considered the spiritual founder of the Democratic Party. Lincoln was the first Republican president, at a time when the party was more about ending slavery than anything else. Even TR might have refused to be identified with today's Republicans. He did, after all, leave the party to run on the Bull Moose ticket in 1912.
Not sure if you saw it, but I touched on this the other day in this thread. There isn't much significance to it other than Coolidge insisted that, in addition to Washington (who had no party affiliation), there were to be two Republicans and one Democrat. Jefferson was a Democratic-Republican, a party which carried on into the Jacksonian Democrats subsequently, and which in turn carried on through to today (in spite of significant ideological changes to meet changing historical circumstances). It comes down to Jefferson, Lincoln, and TR being who Borglum chose, they being, as he felt, representative of American history up until that point, and significant contributors to the expansion/preservation of the country.