and the USAFFE headquarters of General Douglas MacArthur. On December 7, 1941, Japan went to war against the United States, bombing the U.S. naval base in Pearl Harbor, Hawaii while also bombing American bases in the Philippines. Shortly after, Japanese invasion forces landed on Luzon, the largest and most populous of the islands of the Philippine archipelago. MacArthur had claimed that the American–Filipino forces under his command would stop any Japanese invasion "on the beaches", but instead the Japanese forces marched on Manila, the capital and largest city of the Philippines. Roxas accompanied President Quezon to Corregidor where he supervised the destruction of Philippine currency to prevent its capture by the Japanese. When Quezon left Corregidor, Roxas went to Mindanao to direct the resistance there. It was prior to Quezon's departure that he was made executive secretary and designated as successor to the presidency in case Quezon or Vice President Sergio Osmeña were captured or killed. On January 3, 1942, President Quezon presented General MacArthur with a secret guaranty of $500,000. The payment was related to the Filipino concept of utang na loob, where one offers a lavish gift in order to create a reciprocal obligation from the individual who receives the gift. Through the payment was legal, it was questionable from an ethical perspective, and MacArthur always kept the payment secret, which did not become public knowledge until 1979. Later that year, Quezon offered payment to General Dwight D. Eisenhower, which he refused, saying that as a United States Army official, his first loyalty was to the United States, which made accepting such a payment as morally wrong in his viewpoint. Roxas was one of the few people who did know about Quezon's gift to MacArthur. Roxas was captured in April 1942 by the Japanese invasion forces. He became chief advisor to the collaborationist government of José P. Laurel. The American historian Gerhard Weinberg wrote that through many claims have been made that Roxas was secretly a member of the Filipino resistance during the Japanese occupation, no evidence has ever emerged to support these claims. The American journalist Richard Rovere wrote that the evidence that Roxas was actually a resistance fighter was "obscure". Rovere described Roxas as typical of the Filipino hacendado class (the wealthy owners of the hacienda estates) who sought to opportunistically ingratiate themselves with whatever power ruled the Philippines. An additional reason for the hacendados to