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.
Barack Obama's farewell address
Obama served as the first African American President of the United States for two terms, first elected in 2008 and reelected in 2012. During his presidency, his administration addressed the 2007-2008 global financial crisis (including a major stimulus package), oversaw the passage and implementation of the Patient Protection and Affordable Care Act, partially extended Bush tax cuts, took executive action on immigration reform, and took steps to combat climate change and carbon emissions. Obama also authorized the raid that killed Osama bin Laden, signed the New START treaty with Russia, signed the Paris Agreement, and negotiated rapprochements with Iran and Cuba. Democrats controlled both houses of Congress until Republicans won a majority in the House of Representatives in the 2010 elections. 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.