Soldiers of the U.S. Army 3rd Infantry Division secure a field near Najaf, Iraq, at sunrise on March 23, 2003. John Moore/AP hide caption
President George W. Bush
March 20, 2003: U.S. Marines prepare themselves after receiving orders to cross the Iraqi border at Camp Shoup, in northern Kuwait. Eric Feferberg/AFP via Getty Images hide caption
President George W. Bush and Russian President Vladimir Putin speak during a visit to Crawford High School in Crawford, Texas, on Nov. 15, 2001. The appearance wrapped up a summit of the newly elected presidents in Texas. Ronald Martinez/Getty Images hide caption
With Bush in 2001, Putin sought to charm students at a rural Texas high school
An American flag at ground zero on the evening of Sept. 11, 2001, after the terrorist attacks on the World Trade Center in New York City. Mark Lennihan/AP hide caption
Presidents Barack Obama, George W. Bush and Bill Clinton volunteered to take the coronavirus vaccine, once it's available, on camera to assuage concerns about the shot. Icon Sportswire via Getty Images hide caption
The control tower at the Camp VI detention facility in the Guantanamo Bay Naval Base, as seen through razor wire, in April. Alex Brandon/AP hide caption
Flowers are laid at the base of the statue at the George Bush Presidential Library and Museum in College Station, Texas. Suzanne Cordeiro/AFP/Getty Images hide caption
U.S. President George H.W. Bush speaks during a fundraiser in Dallas, on Nov. 1, 1991. Marcy Nighswander/AP hide caption
The President's Daily Briefing is the top-secret intelligence report the CIA presents to the president every weekday. The book shown here is for a briefing delivered to President George W. Bush in 2002. Damian Dovarganes/AP hide caption
Sept. 11 Revealed The Importance And Limits Of The President's Daily Briefing
Smithsonian National Portrait Gallery curator Ann Shumard talks about a photograph of Sen. John McCain, R-Ariz., that was displayed at the gallery on Monday. The former presidential candidate died Saturday of brain cancer at the age of 81. This is the first time that the 2005 image of McCain by photographer Steve Pyke has been displayed in the gallery. Chip Somodevilla/Getty Images hide caption
Sen John McCain, R-Ariz., returns to his office after a series of votes at the Capitol in Washington on Thursday. J. Scott Applewhite/AP hide caption
President John F. Kennedy makes a nationwide televised broadcast on civil rights in the White House, June 11, 1963. Americans often look to presidents for moral clarity in critical moments. Charles Gorry/AP hide caption
Fathers Of Our Country: How U.S. Presidents Exercised Moral Leadership In Crisis
Former President George W. Bush holds an event at his presidential library and museum in Dallas on Feb. 28 for his exhibit of veterans portraits. In interviews about his artwork, Bush has been commenting on the current administration. Laura Buckman/AFP/Getty Images hide caption
Former President George W. Bush poses for photos with students at Warren Easton Charter High School in New Orleans on Friday. He was visiting the city for the 10th anniversary of Hurricane Katrina. Gerald Herbert/AP hide caption
Festivalgoers browse for books during the Miami Book Fair International. PBS will provide live coverage of the fair's events over the course of three days this year. Roberto Schmidt/AFP/Getty Images hide caption
George H.W. Bush (left) congratulates his son George W. Bush as the two former presidents attend last year's dedication of the George W. Bush Presidential Center in Dallas. David J. Phillip/AP hide caption
Before talking about the situation in Iraq, President Obama bantered with (from left to right) Senate Minority Leader Mitch McConnell, House Speaker John Boehner, Senate Majority Leader Harry Reid and House Minority Leader Nancy Pelosi. Pablo Martinez Monsivais/AP hide caption
President Obama walks from the White House to Marine One on Friday. In an interview Thursday with NBC News, he apologized for breaking a promise regarding the Affordable Care Act. J. Scott Applewhite/AP hide caption
President Obama and former President George W. Bush are joined by more than a handshake. Their national security policies link them, too. Charles Dharapak/AP hide caption
Protests like this one in 2010 in Pakistan in part led President Obama to recalibrate when U.S. officials will order drone strikes, as part of a nuanced policy. B.K. Bangash/AP hide caption
Former President George W. Bush speaks alongside former first lady Laura Bush during the opening ceremony of the George W. Bush Presidential Library and Museum on Thursday in Dallas. Kevork Djansezian/Getty Images hide caption