Thomas Jefferson was a statesman who believed that rationality should be the ultimate test of whether or not a government policy should be adopted. If it makes sense from a rational point of view, if it is necessary, and if it is fair, then it should be implemented. If not, then it should not.
One region of American policy in the last several decades that would have shocked and saddened Jefferson would be the disgusting accumulation of vast numbers of nuclear weapons by the United States. The very existence of nuclear weapons would likely have shaken his Enlightenment view of the goodness of humanity, but he would have still insisted on using the power of human reason to craft a rational policy on how to deal with them.
At the height of the Cold War, both the United States and the Soviet Union possessed tens of thousands of nuclear warheads. It was a disgusting absurdity that the two superpowers spent literally trillions of dollars to build vastly more firepower than would have been necessary to obliterate the world many times over.
Since the end of the Cold War, both Russia and America have substantially reduced their nuclear arsenals, but both retain several thousand warheads. Britain, France, China, and Israel all likely have a few hundred each, and India and Pakistan each have built scores of weapons. Carl Sagan referred to nuclear weapons as "genies of death, patiently awaiting the rubbing of the lamps."
Today, the United States possesses roughly 5,400 nuclear weapons, divided between land-based missiles, submarine-based missiles and warheads delivered directly by bombers. This is obscene; there is no rational reason why the country requires such a vast nuclear arsenal. And in an age of severe budget pressures and massive spending deficits, it is absurd to spend tens of billions of dollar a year to maintain such a bloated arsenal.
Ostensibly, the purpose of a nuclear arsenal is to deter an enemy from launching a nuclear attack upon America. But if America were to unilaterally reduce its nuclear arsenal to a few hundred warheads (the size of the nuclear arsenals of the United Kingdom and France), it would still possess as an obvious deterrent against a nuclear attack, because a few hundred warheads is still more than enough to utterly destroy any conceivable combination of enemies. After all, you only need to destroy your enemy once.
President Obama has proven to be a man willing to consider radical shifts away from the policies of the past. He has the option now of initiating a bold and far-sighted policy: unilaterally reduce the American nuclear arsenal to 300 weapons. Furthermore, he could eliminate all land-based based missiles and bomber-delivered weapons, relying only on submarine-based missiles from now on. Sub-based weapons are the safest and most secure in any event, and their continued existence would serve as an effective deterrent against any power foolish enough to launch a nuclear attack on the United States.
Such a unilateral action of the part of the United States would do much to restoring the international reputation of the country, which has suffered so much during the presidency of George W. Bush. It might prompt other nations to consider reducing their stockpiles, or even persuade non-nuclear countries from initiating programs to obtain nuclear weapons that they might otherwise embark upon. It would also save the American taxpayer vast amounts of money, which would do much to reduce the ridiculous budget deficit. Finally, it would simply be in accordance with human nature.
If Jefferson were alive today, he would be among those working towards the ultimate abolition of nuclear weapons throughout the world. Unilaterally reducing our own nuclear arsenal and switching entirely to submarine-based weapons would be a good first step.