The Pentagon Papers, a top-secret U.S. Dept. of Defense study, were leaked to The New York Times in early 1971 by Daniel Ellsberg, who had access to the papers. This document showed that the Johnson administration had secretly been expanding U.S. involvement in the Vietnam War. While there was nothing in the papers about the Nixon administration, Nixon wanted to punish Ellsberg in order to deter other officials who might reveal secrets about his own administration.
Nixon was praised during his presidency for ending American involvement in the Vietnam War.
The Nixon administration dramatically improved relations with China. Nixon made a public visit to China in February, 1972, following Secretary of State Henry Kissinger's secret visit to China in October, 1971.