By the time America elected Barack Obama, this historian would see, it was already on the way down.
Were he to simultaneously examine the rise of the welfare state, he would notice a telltale trend: As socialism dug deeper into the soul of America, America's pioneering spirit waned.
Americans stopped wanting to open new frontiers -- to get there first. Rather than take bold risks and settle new realms, Americans had settled down to wait for the government's largesse.
Fifty years ago last week, a Democratic president gave a speech to a joint session of Congress in which he expressed a different view. In that speech, John F. Kennedy called for Americans to send a man to the moon and bring him back within the 1960s, and to do so not only as an expression of the superiority of freedom over tyranny but as a necessity for maintaining freedom over tyranny.
Six weeks before Kennedy gave this speech, Russian cosmonaut Yuri Gagarin had become the first man to orbit the Earth. Kennedy was clearly disturbed by the propaganda impact this had for Soviet communism.
"(I)f we are to win the battle that is now going on around the world between freedom and tyranny, the dramatic achievements in space which occurred in recent weeks should have made clear to us all, as did the Sputnik in 1957, the impact of this adventure on the minds of men everywhere, who are attempting to make a determination of which road they should take," he told Congress.
Kennedy was also concerned about whether freedom or tyranny would dominate realms beyond the Earth.
"Space is open to us now; and our eagerness to share its meaning is not governed by the efforts of others," said Kennedy. "We go into space because whatever mankind must undertake, free men must fully share."
Having framed the challenge this way, Kennedy said, "I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth."
The historian 2,000 years from now will see, as we can see now, that the America of the 1960s did send men to the moon and back.
The historian will see that the Soviet Union collapsed two decades later.
But then what will he see?
He will see that the U.S. space program stopped being a U.S. space program. Rather than serve to make America first in space, it served as a platform for globaloney. Americans eventually could not even launch their own rockets to bring their own people to and from ... the International Space Station. They relied on Russians.
He will see that even as the U.S. space program declined, U.S. government spending rose as percentage of gross domestic product, pushing past 25 percent in the Obama years.
What he will see climbing into orbit is not U.S. spacecraft, but the U.S debt.
In the first half the 21st century, he will see the U.S. government borrowing tens of trillions -- not to defend the nation against foreign enemies or open new frontiers, but to finance massive entitlement programs.
Last week, former moon astronauts Neil Armstrong, Jim Lovell and Gene Cernan wrote an op-ed in USA Today asking: "Is Obama Grounding JFK's Space Legacy?" Obama's 2011 budget proposal, they noted, defunded NASA's Constellation program, which called for returning men to the moon and eventually sending men to Mars. While Congress restored funding, the former astronauts pointed out, Obama's 2012 budget proposal reduced it again.
"Today, under the announced objectives (of the Obama administration), the voyage is over," wrote Armstrong, Lovell and Cernan. "John F. Kennedy would have been sorely disappointed."
But will Obama's vision -- or lack of it -- prevail?
Former astronaut Jack Schmitt -- who on Dec. 11, 1972, emerged from the lunar module in the Valley of Taurus-Littrow to became the last man to step onto the moon -- told me last week that NASA should be phased out so it can be replaced with a new National Space Exploration Administration (NSEA).
"I think the vast majority (of Americans) recognize that the United States represents liberty and freedom on this planet, and if it is not competitive in space, well then, liberty and freedom are in further jeopardy than they are for other reasons," said Schmitt, who also served as a Republican senator from New Mexico and as chairman of NASA's advisory council.
"The NSEA would be given the charter to explore deep space, which includes the moon, to settle the moon and ultimately potentially to settle Mars, and to help the private sector utilize the resources, the energy resources in particular, that we find on the moon," said Schmitt.
Schmitt, like me, is an admirer of the historian Frederick Jackson Turner, who argued that the unique success of freedom and representative government in America is tied to our pioneering heritage and the pioneering spirit it engendered.
Let's keep that spirit alive -- here and on the next frontier.