President Barack Obama has said he did not oversell his plan to fix the struggling US economy, insisting the nation's woes had been mounting for 20 years, in comments to CBS News. "I didn't overpromise. And I didn't underestimate how tough this was going to be," Obama said, according to excerpts from an interview to be broadcast in full on the CBS News program "60 Minutes" on Sunday. "I always believed that this was a long-term project. Reversing structural problems in our economy that have been building up for two decades, that was going to take time," after entering office, the president said. "It was going to take more than a year. It was going to take more than two years. It was going to take more than one term. Probably takes more than one president," Obama said. Obama, who defeated Republican nominee John McCain in the 2008 election on a promise of "Yes We Can," entered the White House in January 2009 while the US economy was still in recession as a result of the global financial crisis. During the campaign, Obama had pledged to restore America's economic dominance and gained the upper hand in a tight race after McCain blundered on the economy. Although the United States exited the recession under Obama's leadership, the American economy has been plagued by high unemployment since, and despite falling last month, joblessness remains stubbornly high at 8.6 percent. Obama admitted in the interview that Americans "who are struggling right now, they have every reason to be impatient," but likened himself to the captain of a ship "going through really bad storms." "No matter how well we're steering the ship, if the boat's rocking back and forth and people are getting sick and...they're being buffeted by the winds and the rain," the president said. "People are going to say, 'You know what? A good captain would have had us in some smooth waters and sunny skies, at this point.' And I don't control the weather," Obama added. Asked if unemployment could fall to eight percent before the November 2012 presidential election, he replied: "It's possible. But...I'm not in the job of prognosticating on the economy. I'm in the job of putting in place the tools that allow the economy to thrive and Americans to succeed."