WASHINGTON — After three debates and four and a half hours of nationally televised exchanges, Americans have learned that President Obama has a smaller pension than his opponent and Mitt Romney wants to get Big Bird’s beak out of the federal trough, that Joseph R. Biden Jr. likes to smile and Paul D. Ryan drinks lots of water.

But they have not learned as much about what the next four years might look like. With tens of millions of Americans tuning in to the debates, the four candidates for president and vice president have spent most of their time on the biggest public stage of the campaign fighting more about what happened in the last term than what should happen in the next.

Mr. Obama and Vice President Biden defended their record but gave only a modest sense of their agenda should they be re-elected, beyond arguing for staying the course because the other side would return to what they called the failed policies of the past. Mr. Romney and his running mate, Mr. Ryan, did offer a vision of sorts for replacing what they called failed policies of the present, but they declined to give the kind of details that would help voters evaluate what it would mean for them.

As a result, voters are left to extrapolate from the signals sent during the debates what the future would hold under an Obama second term or a first term of a President Romney. Americans can make interpretations from the values and concepts expressed, even if there are few tangible plans to consider.