I have to go with Ronald Reagan.
I’m sure someone will chime in with Jefferson Davis. LOL!
No Way! Ronald gave us Sandra Day O’Conner & gave the USSR tons of cash that never made it! He also compromised himself & this country during the Iran Contra scandel by breaking the Boland amendment. Granted he was a breath of fresh air as to what we have now.
George Washington & gang did not & would not approve of any forms of Taxation that we have today! they did not & would not have approved or even considered an individual Social(ist) (in)Security number or any kind or tax identification numbers, no kinds of welfare or government handouts of anykind all of those we still had under Reagan.
I'm sure that Ronaldus Magnus would give you a quizzical look with a steely eye, then vote for Washington.
I recently finished reading "1776" by David McCullough. Much of the book revolves around George Washington's efforts to build the Continental Army, all while fighting our first battles with the British at the same time.
The sheer enormity of the task that our first CIC confronted, and successfully dealt with, is unparalleled in our history. There was little guarantee that he would succeed in that task at the time, and most Americans gave him small odds of doing so, yet he and other patriots did the impossible, and won our people's freedom.
He went on to serve admirably as our first President, and with the sort of dignity and integrity to the office that has rarely been seen since.
It's too easy to call any modern American president, "the greatest of all time". Only a thorough reading of history can bring out the lives and deeds of our former presidents vividly enough for a real comparison to those we remember from our lifetimes.