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.
Presidency of Barack Obama
In his second term, Obama took steps to combat climate change, signing a major international climate agreement and an executive order to limit carbon emissions. Obama also presided over the implementation of the Affordable Care Act and other legislation passed in his first term, and he negotiated rapprochements with Iran and Cuba. The number of American soldiers in Afghanistan fell dramatically during Obama's second term, though U.S. soldiers remained in Afghanistan throughout Obama's presidency and continue to as of 2018. Republicans took control of the Senate after the 2014 elections, and Obama continued to grapple with Congressional Republicans over government spending, immigration, judicial nominations, and other issues.