Our country was founded because of the efforts of progressive thinkers. They had the audacity to suggest that all men are created equal. Since then, as a country, we've stumbled forward. We fought a civil war to ensure that no one was denied their rights as US citizens because of the color of their skin. We behaved atrociously to the indigenous population. Women didn't have the right to vote until the early 1900's.
Even with all the set-backs to basic human rights, there were still plenty of progressive thinkers in the US. From Ben Franklin to President Woodrow Wilson to President Kennedy, there was progressive thinking for the sciences as well.
Benjamin Franklin supposedly experimented by flying a kite to test the theory that electricity and lightening were the same. He was also a prolific inventor and his Franklin stove is still in use today.
I choose President Woodrew Wilson because of progressive thinking of the theory of evolution:
Of course, like every other man of intelligence and education I do believe in organic evolution. It surprises me that at this late date such questions should be raised.
Letter to Winterton C. Curtis (29 August 1922)
President Kennedy started one of the greatest periods of technological in the US when he vowed that we would send a man to the moon.
As a country, we were much more progressive in our thinking in the 1950's and the 1960's. Schools seemed to be geared to teaching US kids science and math courses that would help our country progress. Television shows like Watch Mr. Wizard are still fun to watch today.
When my son was growing up in the early 1990's, we watched Bill Nye, The Science Guy. It was awesome to watch the Space Shuttle and the Hubble Telescope. Those pictures are enough to see the value of progressive thinking.
The Space Shuttles have been grounded. The US must rely on Russia and other countries to get into space. This is something that would have been unthinkable 50 years ago. Progressive thinking led us into great discoveries and the lack now is leading us backwards. It doesn't help that the majority of Republican candidates for president have such a narrow view-point on science.