Despite the fact that a presidential term lasts four years, the truth is that the endless election cycle gives modern presidents very little time to push through their agendas. And according to some observers, President Obama may have already missed his window to tick some very important boxes, from an immigration overhaul to budget reform.

In politics, success engenders success, and in the wake of the government shutdown the White House appeared to be in a dominant position to either roll up some legislative victories or punish Republicans at the polls in 2014. Then ObamaCare happened, leading to a corollary political maxim: Failure begets failure.

The administration so badly bungled the ObamaCare rollout that Obama has lost the faith of the American people, putting him in no position to bully lawmakers — Republicans or Democrats — into working his will. Obama will have to toil long and hard to regain his advantage, at which point the political world may be already turning its gaze to 2016.

In particular, the president's broken promise that people could keep their health-insurance plans has dramatically undercut Obama's credibility. A recent Quinnipiac survey found that, for the first time in his presidency, a majority of voters did not believe Obama was "trustworthy," a startling finding for a president whose greatest political asset was that he was at least considered an honest broker.

Though there is plenty of time to resuscitate ObamaCare, the "untrustworthy" tag could linger over Obama's presidency going forward. George W. Bush and Bill Clinton both lost the public trust in their second terms and never fully recovered, wrote The Washington Post's Dana Milbank, and Obama's dismal poll numbers could signal the same dilemma.

"Once a president suffers a blow such as Obama is now suffering with his health-care law — in which the public not only disapproves of a president's actions but starts to take a negative view of him personally — it is difficult to recover," he wrote.

Furthermore, Obama's response to ObamaCare's woes hasn't exactly inspired much confidence. The much-publicized fix for those who want to keep their old insurance plans will probably have little impact — and if it does, it will only weaken the overall law, upon which the Democratic Party's credibility rests.

As Edward Luce wrote in the Financial Times:

Mr Obama’s problems derive chiefly from his tendency to react politically to events, rather than from a lack of time. His fumbling response to the woes engulfing the Affordable Care Act show how hard it is for him to kick the habit — even if the remainder of his presidency depends on it. [Financial Times]

He adds, "There is little reason to be confident Mr Obama’s power will rally sharply from this nadir."

The good news for Obama, however, is that the law itself may actually be performing better than is generally portrayed in the press. As Jonathan Chait at New York points out, other goals of the law — including expanding Medicaid and lowering costs — are being met, and in some cases exceeding expectations. If the federal exchange website ever starts working, the law's image could be on the road to recovery.

"The most common fallacy of journalism," Chait writes, "and one of the most common fallacies of the human brain in general, is the assumption that whatever is happening at the moment will continue to happen forever."

Politics is a volatile, unpredictable business. Remember how the conventional wisdom just one month ago held that Republicans had thrown the 2014 elections with their government shutdown tantrum, and risked becoming yet another dustbin party? So much for that.

Obama's approval rating fell to around 40 percent once before, in August 2011, according to Gallup; within a year, it had climbed back over the 50 percent threshold.

Still, there are precious few opportunities to turn around public opinion. To win back the country's trust, the administration will have to start stringing together some victories and show a level of competence that has been disturbingly lacking in the ObamaCare debut.