James Stavridis is a retired four-star U.S. Navy admiral and NATO supreme allied commander who serves today as the dean of the Fletcher School of Law and Diplomacy at Tufts University. His latest book is The Leader's Bookshelf.
KORENGAL VALLEY, AFG - OCTOBER 27: U.S. soldiers board an Army Chinook transport helicopter after it brought fresh soldiers and supplies to the Korengal Outpost October 27, 2008. The military spends huge effort and money to fly in supplies to soldiers of the 1-26 Infantry based in the Korengal Valley, site of some of the fiercest fighting of the Afghan war. The unpaved road into the remote area is bad and will become more treacherous with the onset of winter. (Photo by John Moore/Getty Images)
TOPSHOT - Cuban Americans in Miami's Little Havana celebrate the death of longtime Cuban leader Fidel Castro on November 26, 2016.
Cuba's socialist icon and father of his country's revolution Fidel Castro died on November 25 aged 90, after defying the US during a half-century of ironclad rule and surviving the eclipse of global communism. / AFP / RHONA WISE (Photo credit should read RHONA WISE/AFP/Getty Images)
A computer running a Windows Server is seen connected into a network server in an office building in Washington, DC on May 13, 2017.
International investigators hunted on May 13 for those behind an unprecedented cyber-attack that affected systems in dozens of countries, including at banks, hospitals and government agencies, as security experts sought to contain the fallout. The assault, which began Friday and was being described as the biggest-ever cyber ransom attack, struck state agencies and major companies around the world -- from Russian banks and British hospitals to FedEx and European car factories. / AFP PHOTO / Andrew CABALLERO-REYNOLDS (Photo credit should read ANDREW CABALLERO-REYNOLDS/AFP/Getty Images)
HEMPSTEAD, NY - SEPTEMBER 26: Republican presidential nominee Donald Trump waves after the Presidential Debate with Democratic presidential nominee Hillary Clinton at Hofstra University on September 26, 2016 in Hempstead, New York. The first of four debates for the 2016 Election, three Presidential and one Vice Presidential, is moderated by NBC's Lester Holt. (Photo by Drew Angerer/Getty Images)
ANNAPOLIS, MD - JULY 01: Incoming U.S. Navy plebes, or freshmen, are taught how to salute on their first day at the U.S. Naval Academy July 1, 2015 in Annapolis, Maryland. Over 1,193 Plebes will be processed through various stations that will culminate with the Oath of Office ceremony to become members of the Naval Academy's Class of 2019. (Photo by Mark Wilson/Getty Images)
BERLIN, GERMANY - JUNE 03: Egyptian President Abdel Fattah el-Sisi wipes his brow during a news conference with German Chancellor Angela Merkel (unseen) on June 3, 2015 in Berlin, Germany. The meeting between the two leaders was intended to increase economic and security cooperation between their two countries, which shared 4.4 billion euros ($4.8 billion) in bilateral trade in 2014. The two disagreed over human rights issues such as capital punishment. (Photo by Adam Berry/Getty Images)
(FILE) Cuban president, Fidel Castro, inaugurates several newly built areas added to an old Havana hospital, 05 June 1989. AFP PHOTO/FILE/RAFAEL PEREZ (Photo credit should read RAFAEL PEREZ/AFP/Getty Images)
HEMPSTEAD, NY - SEPTEMBER 26: Republican presidential nominee Donald Trump waves after the Presidential Debate with Democratic presidential nominee Hillary Clinton at Hofstra University on September 26, 2016 in Hempstead, New York. The first of four debates for the 2016 Election, three Presidential and one Vice Presidential, is moderated by NBC's Lester Holt. (Photo by Drew Angerer/Getty Images)
NEW YORK, NY - NOVEMBER 10: Network cables are plugged in a server room on November 10, 2014 in New York City. U.S. President Barack Obama called on the Federal Communications Commission to implement a strict policy of net neutrality and to oppose content providers in restricting bandwith to customers. (Photo by Michael Bocchieri/Getty Images)
HANGZHOU, CHINA - SEPTEMBER 04: President Vladimir Putin of Russia (L) arrives at the Hangzhou Exhibition Center to participate in G20 Summit, on September 4, 2016 in Hangzhou, China. World leaders are gathering in Hangzhou for the 11th G20 Leaders Summit from September 4 to 5. (Photo by Etienne Oliveau/Getty Images)
WASHINGTON, DC - FEBRUARY 03: Activists hold a rally to protest the Trans-Pacific Partnership (TPP) in front of the White house on February 3, 2016 in Washington, DC. The TPP trade pact is expected to be signed in New Zealand on February 4. (Photo by Olivier Douliery/Getty Images)
NEW YORK, NY - SEPTEMBER 28: (AFP OUT) U.S. President Barack Obama (L) and Russian President Valdimir Putin toast during a luncheon hosted by United Nations Secretary-General Ban Ki-moon during the 70th annual UN General Assembly at the UN headquarters September 28, 2015 in New York City. Obama held a bilateral meeting with Indian Prime Minister Narendra Modi and with have a face-to-face meeting with Putin later in the day. (Photo by Chip Somodevilla/Getty Images)
GBARNGA, LIBERIA - OCTOBER 07: U.S. Navy microbiologist Lt. Jimmy Regeimbal prepares to test blood samples for Ebola at the U.S. Navy mobile laboratory of on October 7, 2014 near Gbarnga in Bong County of central Liberia. The U.S. now operates 4 mobile laboratories in Liberia as part of the American response to the Ebola epidemic. The disease has killed more than 3,400 people in West Africa, according to the World Health Organization. (Photo by John Moore/Getty Images)
