The president has left it largely to others in his administration to outline the U.S. role in Japan's recovery, but he made a Rose Garden appearance Thursday to calm Americans, some of whom have started hoarding potassium iodide tablets to protect themselves from radiation even though health experts said they don't need the pills.
"I want to be very clear: We do not expect harmful levels of radiation to reach the United States, whether it's the West Coast, Hawaii, Alaska, or U.S. territories in the Pacific," Obama said. "Furthermore, the Centers for Disease Control and Prevention and public health experts do not recommend that people in the United States take precautionary measures beyond staying informed."
Obama spoke while Japanese officials were struggling to cool three dangerously overheated nuclear reactors and pools used to store spent nuclear fuel rods that threaten to spread contamination across the island nation. U.S. officials conducted multiple radioactivity tests on the scene and told Americans living within 50 miles of the endangered nuclear plants to evacuate. The Japanese had said the plants were a threat only to residents living within 12 miles.
Obama also called for the Nuclear Regulatory Commission to conduct a "comprehensive review" of the nation's 104 nuclear reactors -- while continuing to voice support for a power source that provides one-fifth of America's electricity.
"Our nuclear power plants have undergone exhaustive study, and have been declared safe for any number of extreme contingencies," he said. "But when we see a crisis like the one in Japan, we have a responsibility to learn from this event, and to draw from those lessons to ensure the safety and security of our people."
Yet, members of his own party are clamoring for the president to impose a moratorium on nuclear plant construction, pointing to China and Germany, both of which put nuclear projects on hold following the earthquake and tsunami that damaged the Japanese plants.
The president made an unscheduled trip Thursday to the Japanese Embassy, where he signed a condolences book for the thousands killed in the disaster.
Contradictory reports about the scope of danger around the Japanese nuclear facility have led to questions about whether the Obama administration can rely on information provided by Japanese officials, though U.S. officials were careful not to criticize their Japanese counterparts during a White House briefing Thursday.
"I want to stress this is a prudent and precautionary measure to take," Gregory Jaczko, chairman of the Nuclear Regulatory Commission, said of the discrepancy between the 50-mile American evacuation zone versus the 12-mile area recommended by Japanese officials. He said the crisis could "last for weeks."
Congressional Republicans and others have criticized Obama for perceived inaction following events in Japan and deadly revolts spreading across the Middle East, but Obama vowed to keep Americans apprised of events in Japan.
"Going forward, we will continue to keep the American people fully updated, Obama said, "because I believe that you must know what I know as president."