George Washington
At the end of his second term, Washington retired for personal and political reasons, fatigued and disgusted with personal attacks, and to assure a truly contested presidential election could be held. He did not feel bound to a two-term limit, but his retirement ultimately set precedent. The two-term limit to the presidency was formalized with the 1951 adoption of the Twenty-second Amendment to the United States Constitution. Washington is often credited with setting the principal of a two-term presidency, but it was Thomas Jefferson who first refused to run for a third term on political grounds.
Second-term curse
Whether this perceived tendency is real is a subject of dispute: for example, political statistician Nate Silver, after analyzing presidential approval ratings for Harry S. Truman through Barack Obama, did find that approval ratings were lower on average during second terms, but he also found a variety of other reasons to explain those ratings, and he concluded that "the idea of the second-term curse is sloppy as an analytical concept". In addition, political writer Michael Barone cited several presidents who had successful second terms, and wrote that "second-term problems resulted more often from the failure to adjust to changed circumstances and unanticipated challenges". Conversely, a 2013 report in "The Economist" has said that the existence of the second-term curse is supported by data. The report stated that each of the eleven second terms served from the beginning of the Theodore Roosevelt administration to the end of the George W. Bush administration were less economically prosperous than their respective president's first term, save for the second terms of Truman, Ronald Reagan, and Bill Clinton.