Thanks to the legacy of Franklin Roosevelt, political analysts and news reporters traditionally measure a president’s progress after the first 100 days. Such evaluations are at best shallow and incomplete and in many ways irrelevant to the future success or failure of a president.

But what about the first 1,000 days? Perhaps this milestone makes more sense. In his 1961 inauguration address, President John F. Kennedy mentioned the first 1,000 days, or much longer, as the time needed in the quest for global cooperation and world peace. The time frame might be applied as a point of reflection on the merits of a presidency.

As political scientist Charles Jones has pointed out, as time goes by the president makes more decisions, faces more unpredictable events (both foreign and domestic), deals with Congress across a wider range of issues, undergoes staff changes, is subjected to more criticism (always from opponents and sometimes from allies) and is judged at least once by a midterm election. Thus, the president is more tested at the 1,000 day mark and is much closer to the ultimate judgment—a re-election campaign.

The presidency and the future beyond it look a lot different for President Obama after the first 1,000 days than they did after the first 100 days. To begin with the policy agenda has changed, as it always does, driven more by events and unforeseen political developments than the president’s campaign promises. A program that involved a massive expansion of government and deficit spending certified by a Democratically controlled Congress in 2009 has given way to “balanced” economic plan in October 2011. In the wake of major losses by his party in the 2010 midterm elections, President Obama’s recent spending initiatives and tax cuts have to be paid for and agreed to by a Republican majority in the House and a diminished Democratic majority in the Senate.

In its own uncoordinated and combative way, Washington has reached consensus that the federal debt matters, and thus no fiscal plan can proceed without facing it. The exploding debt is an unhappy circumstance for any elected official, but it is especially problematic for a president who believes more government spending is the answer to the nation’s economic troubles.

The president’s “power” has also declined. As the late political scientist Richard Neustadt observed, presidential power is the power to persuade other people who share power (congressional leaders, presidential appointees, lobbyists and groups, foreign leaders, the news media, and the public) that it is in their interest to go along with the president. The president’s persuasive power is partly a function of his personal skills, but also a result of how others perceive his status and prestige.

By this standard, in the first 100 days of his presidency, Obama had tremendous power. Today, like other presidents who have suffered a similar fate, Obama’s diminished power has been affected partly by conditions he cannot control and partly from his own decisions. A controversial battle over health care (which remains unresolved), a stubborn economy racked by a housing crisis, banking and credit problems, persistent unemployment, and a series of apparent missteps in handling a range of issues from Guantanamo Bay to Solyndra have overshadowed President Obama’s successes.

An overwhelming majority of Americans believe the country is on the wrong track, shorthand for saying the president is not doing the job we expect of him. As the nation goes, so goes the power of the president.

Having lost power inside of Washington, presidents often appeal to the public for support, as Obama has done with his jobs bill. Such efforts to rally the public are usually acts of desperation, at least in terms of influencing Congress. The public seems to be moved more by the world they experience than by a president’s rhetorical skill. Not surprisingly, since the president began the public campaign for his jobs bill, his approval rating has barely budged. Thus he looks even weaker among his opponents for trying and failing to rally public support. As some have observed, the goal of the “jobs bill” may be to frame the debate for the election campaign rather than to jumpstart the economy.

As that campaign approaches, a president who after 100 days may have seemed invincible is now quite vulnerable to defeat. At the 1,000 day mark, the president’s re-election strategy has taken shape and is defined as much by the conditions he faces than choices he might otherwise make.

Candidate Obama’s 2008 message of hope and change (peppered with criticism of his predecessor’s record) that promised to unify the nation and reconcile partisan divisions is a distant memory. In 2012, President Obama would have to be satisfied with a narrow majority gained by mobilizing the Democratic voting base, avoiding evaluations of his record or of his promises in 2008, emphasizing the “choice” between himself and an unworthy Republican candidate, and targeting key battleground states with messages tailored to regional populations. Such is the effect of the first 1,000 days of the Obama presidency.

Daniel J. Palazzolo is a professor of political science at the University of Richmond.