As he enters the Back Nine of his second term in office, President Barack Obama is clearly looking to establish his historical legacy. No doubt, his highest priority is the preservation of the Affordable Care Act, which his Administration views as no less important than Medicare and Social Security. Whether Obamacare will survive in its present form, or even survive at all, of course, remains an open question that will be determined both by the future composition of Congress and by the policy preferences of the next White House occupant.

In addition, it is clear that he wishes to be remembered as the president who defeated Al Qaeda by authorizing the successful operation to kill Osama Bin Laden. This legacy, too, is uncertain. It is not merely the host of unanswered questions about the Benghazi fiasco. More to the point is the fact that Islamic extremists, who are at the center of both the Syrian and renewed Iraqi civil wars, are increasingly assertive and violent in Africa and are far from dormant in Southeast Asia as well.

Finally, and most critically, the president is determined to be remembered as the man who ended two wars while avoiding a new one. And in this case, even more than in the others, it will be impossible to evaluate that legacy, much less confirm it, for years to come. The war in Iraq has indeed come to an end, but only for Americans. It continues to rage between Sh'ia and Sunni elements. Iran continues to maintain its influence in Baghdad. Indeed, many informed Iraqis consider that Tehran's influence in Iraq outweighs that of the United States. Moreover, Iran has been the leading supporter of Bashar al-Assad's bloody campaign to quash the Syrian opposition. Its deleterious impact on regional stability could well be sustained for years to come.

The withdrawal from Afghanistan may lead to similar unfortunate results. The fact that former foreign minister and leading presidential contender Abdullah Abdullah is now receiving support from Hamid Karzai's chosen candidate, Zalmai Rassoul, calls into question whether the United States will continue to maintain troops in Afghanistan in the event Abdullah assumes the presidency, given Karzai's hostility to Washington. Moreover, even if some American troops remain in that country, given all indications from the administration, that number will be severely limited, perhaps to the point where direct American impact on Afghanistan's future will be minimal.

Even more than the withdrawals from Iran and Afghanistan, the president's clear determination to avoid any American foreign entanglement, defining any alternative to his approach as solely that of prosecuting a military campaign, has sent an unequivocal message to the world that America is in a state of retreat. That message has been reinforced by presidential passivity, if not approval, in the face of ongoing reductions to the defense budget.

The message of American retreat from its historic role as the leader of the Free World is not one that the president has intended to transmit, and indeed has protested against. It is now a universally accepted perception, however, and therefore has become increasingly difficult for the administration to counter. Moreover, it is a perception that, absent a major change in policy leading to renewed American international assertiveness (not military engagement, but assertiveness) for the remainder of the president's term, could linger for years. It has the potential to cause possible irreversible harm to America's international standing.

It is not only Vladimir Putin who has taken the measure of American passivity, and has acted accordingly in Crimea and Ukraine. So have the Chinese, who have clashed with Vietnam recently in the South China Sea, and have been increasingly confrontational vis-à-vis Japan over their competing claims to the Daioyu/Senkaku Islands. No doubt the Iranians, North Koreans, and various Al Qaeda offshoots have likewise factored the perceived American withdrawal from the world into their own strategies.

It is not only potential and actual adversaries who are modifying their strategies based on their perception of American passivity. Egypt, an American partner for decades, has openly announced that it is reaching out to Russia at a time when Moscow is increasingly seen in the West as a threat to international stability. India has likewise backed away from closer cooperation with Washington, as its traditional relations with Moscow have remained warm; India was one of the few countries voicing outspoken support for Russia's takeover of the Crimea. No less than fifty-eight countries, including most African states, Israel, China and Argentina, abstained in the General Assembly's condemnation of Russia for its annexation of Crimea, despite intense American lobbying for their votes. The failure of the latest attempt to foster a peace agreement between Israelis and Palestinians is due in no small part to the perception on both sides that Mr. Obama is simply less personally engaged in foreign policy matters than any of his predecessors reaching as far back as Herbert Hoover. Finally, America's Central European NATO allies have become increasingly worried that American passivity will encourage Moscow to pressure them once Russia has carried out its objectives vis-à-vis Ukraine.

The president's long-standing commitment to "nation building at home" at the expense of maintaining America's standing abroad simply has overlooked the fact that, as former Vice Chairman of the Joint Chiefs of Staff, Gen. James Cartwright, emphatically stressed, "the enemy gets a vote." The Administration’s desperate effort to deal with foreign affairs at arms-length could well enmesh the United States in another war against an aggressor that misconstrued temporary passivity as long-term weakness. Such a conflict may well take place after the election of a new president. But should it come to pass, it will be the lasting and dominating legacy of none other than President Barack Obama.

Dov Zakheim served as the undersecretary of defense (comptroller) and chief financial officer for the U.S. Department of Defense from 2001–2004 and as the deputy undersecretary of defense (planning and resources) from 1985-1987. He also served as DoD's civilian coordinator for Afghan reconstruction from 2002–2004. He is a member of The National Interest's advisory council.