1988: April

April 4 - Governor Evan Mecham of Arizona is convicted in his impeachment trial and removed from office.
April 5 - Massachusetts Governor Michael Dukakis wins the Wisconsin Democratic presidential primary.
April 10 - The Ojhri Camp Disaster occurs in Islamabad and Rawalpindi.
April 10 - The Great Seto Bridge opens to traffic in Japan.
April 11 - The Last Emperor (directed by Bernardo Bertolucci) wins nine Oscars.
April 12 - Former pop singer Sonny Bono is elected mayor of Palm Springs, California.
April 14 - In the Geneva Accords, the Soviet Union commits itself to withdrawal of its forces from Afghanistan.
The USS Samuel B. Roberts (FFG-58) strikes a naval mine in the Persian Gulf, while deployed on Operation Earnest Will during the Tanker War phase of the Iran–Iraq War.
April 16 - Israeli commandos kill the PLO's Abu Jihad in Tunisia.
April 16 - In Forlì, Italy, the brigate rosse kill Senator Roberto Ruffilli, an advisor of Prime Minister Ciriaco de Mita.
April 18 - United States Navy retaliates for the Roberts mining with Operation Praying Mantis, in a day of strikes against Iranian oil platforms and naval vessels.
April 25 - In Israel, Ivan Demjanjuk is sentenced to death for war crimes committed in World War II. He was accused by survivors of being the notorious guard at the Treblinka extermination camp known as "Ivan the Terrible". The conviction is later overturned by the Israeli Supreme Court.
April 28 - Aloha Flight 243 loses several yards of its upper fuselage while in flight, killing one.
April 30 - World Expo '88 opens in Brisbane Queensland, Australia.